Version 2.0.0

* refactor: remove deprecated parameter and function

* refactor: centralize type aliases in types.py and simplify crud layer

* test: add missing tests for fixtures/utils.py

* refactor: simplify and deduplicate across crud, metrics, cli, and
exceptions

* docs: fix old Paginate references

* docs: add migration + fix icon

* docs: update README/migration to v2

README.md

@@ -20,7 +20,7 @@ A modular collection of production-ready utilities for FastAPI. Install only wha
 
 ## Installation
 
-The base package includes the core modules (CRUD, database, schemas, exceptions, fixtures, dependencies, logging):
+The base package includes the core modules (CRUD, database, schemas, exceptions, fixtures, dependencies, model mixins, logging):
 
 ```bash
 uv add fastapi-toolsets
@@ -29,9 +29,9 @@ uv add fastapi-toolsets
 Install only the extras you need:
 
 ```bash
-uv add "fastapi-toolsets[cli]"      # CLI (typer)
-uv add "fastapi-toolsets[metrics]"  # Prometheus metrics (prometheus_client)
-uv add "fastapi-toolsets[pytest]"   # Pytest helpers (httpx, pytest-xdist)
+uv add "fastapi-toolsets[cli]"
+uv add "fastapi-toolsets[metrics]"
+uv add "fastapi-toolsets[pytest]"
 ```
 
 Or install everything:
@@ -48,6 +48,7 @@ uv add "fastapi-toolsets[all]"
 - **Database**: Session management, transaction helpers, table locking, and polling-based row change detection
 - **Dependencies**: FastAPI dependency factories (`PathDependency`, `BodyDependency`) for automatic DB lookups from path or body parameters
 - **Fixtures**: Fixture system with dependency management, context support, and pytest integration
+- **Model Mixins**: SQLAlchemy mixins for common column patterns (`UUIDMixin`, `CreatedAtMixin`, `UpdatedAtMixin`, `TimestampMixin`)
 - **Standardized API Responses**: Consistent response format with `Response`, `PaginatedResponse`, and `PydanticBase`
 - **Exception Handling**: Structured error responses with automatic OpenAPI documentation
 - **Logging**: Logging configuration with uvicorn integration via `configure_logging` and `get_logger`

docs/examples/pagination-search.md

@@ -1,6 +1,6 @@
 # Pagination & search
 
-This example builds an articles listing endpoint that supports **offset pagination**, **cursor pagination**, **full-text search**, and **faceted filtering** — all from a single `CrudFactory` definition.
+This example builds an articles listing endpoint that supports **offset pagination**, **cursor pagination**, **full-text search**, **faceted filtering**, and **sorting** — all from a single `CrudFactory` definition.
 
 ## Models
 
@@ -16,7 +16,7 @@ This example builds an articles listing endpoint that supports **offset paginati
 
 ## Crud
 
-Declare `facet_fields` and `searchable_fields` once on [`CrudFactory`](../reference/crud.md#fastapi_toolsets.crud.factory.CrudFactory). All endpoints built from this class share the same defaults and can override them per call.
+Declare `searchable_fields`, `facet_fields`, and `order_fields` once on [`CrudFactory`](../reference/crud.md#fastapi_toolsets.crud.factory.CrudFactory). All endpoints built from this class share the same defaults and can override them per call.
 
 ```python title="crud.py"
 --8<-- "docs_src/examples/pagination_search/crud.py"
@@ -46,14 +46,14 @@ Declare `facet_fields` and `searchable_fields` once on [`CrudFactory`](../refere
 
 Best for admin panels or any UI that needs a total item count and numbered pages.
 
-```python title="routes.py:1:27"
---8<-- "docs_src/examples/pagination_search/routes.py:1:27"
+```python title="routes.py:1:36"
+--8<-- "docs_src/examples/pagination_search/routes.py:1:36"
 ```
 
 **Example request**
 
 ```
-GET /articles/offset?page=2&items_per_page=10&search=fastapi&status=published
+GET /articles/offset?page=2&items_per_page=10&search=fastapi&status=published&order_by=title&order=asc
 ```
 
 **Example response**
@@ -83,14 +83,14 @@ GET /articles/offset?page=2&items_per_page=10&search=fastapi&status=published
 
 Best for feeds, infinite scroll, or any high-throughput API where offset performance degrades.
 
-```python title="routes.py:30:45"
---8<-- "docs_src/examples/pagination_search/routes.py:30:45"
+```python title="routes.py:39:59"
+--8<-- "docs_src/examples/pagination_search/routes.py:39:59"
 ```
 
 **Example request**
 
 ```
-GET /articles/cursor?items_per_page=10&status=published
+GET /articles/cursor?items_per_page=10&status=published&order_by=created_at&order=desc
 ```
 
 **Example response**

docs/index.md

@@ -20,7 +20,7 @@ A modular collection of production-ready utilities for FastAPI. Install only wha
 
 ## Installation
 
-The base package includes the core modules (CRUD, database, schemas, exceptions, fixtures, dependencies, logging):
+The base package includes the core modules (CRUD, database, schemas, exceptions, fixtures, dependencies, model mixins, logging):
 
 ```bash
 uv add fastapi-toolsets
@@ -29,9 +29,9 @@ uv add fastapi-toolsets
 Install only the extras you need:
 
 ```bash
-uv add "fastapi-toolsets[cli]"      # CLI (typer)
-uv add "fastapi-toolsets[metrics]"  # Prometheus metrics (prometheus_client)
-uv add "fastapi-toolsets[pytest]"   # Pytest helpers (httpx, pytest-xdist)
+uv add "fastapi-toolsets[cli]"
+uv add "fastapi-toolsets[metrics]"
+uv add "fastapi-toolsets[pytest]"
 ```
 
 Or install everything:
@@ -44,10 +44,11 @@ uv add "fastapi-toolsets[all]"
 
 ### Core
 
-- **CRUD**: Generic async CRUD operations with `CrudFactory`, built-in full-text/faceted search and offset/cursor pagination.
+- **CRUD**: Generic async CRUD operations with `CrudFactory`, built-in full-text/faceted search and Offset/Cursor pagination.
 - **Database**: Session management, transaction helpers, table locking, and polling-based row change detection
 - **Dependencies**: FastAPI dependency factories (`PathDependency`, `BodyDependency`) for automatic DB lookups from path or body parameters
 - **Fixtures**: Fixture system with dependency management, context support, and pytest integration
+- **Model Mixins**: SQLAlchemy mixins for common column patterns (`UUIDMixin`, `CreatedAtMixin`, `UpdatedAtMixin`, `TimestampMixin`)
 - **Standardized API Responses**: Consistent response format with `Response`, `PaginatedResponse`, and `PydanticBase`
 - **Exception Handling**: Structured error responses with automatic OpenAPI documentation
 - **Logging**: Logging configuration with uvicorn integration via `configure_logging` and `get_logger`

docs/migration/v2.md

@@ -0,0 +1,137 @@
+# Migrating to v2.0
+
+This page covers every breaking change introduced in **v2.0** and the steps required to update your code.
+
+---
+
+## CRUD
+
+### `schema` is now required in `offset_paginate()` and `cursor_paginate()`
+
+Calls that omit `schema` will now raise a `TypeError` at runtime.
+
+Previously `schema` was optional; omitting it returned raw SQLAlchemy model instances inside the response. It is now a required keyword argument and the response always contains serialized schema instances.
+
+=== "Before (`v1`)"
+
+    ```python
+    # schema omitted — returned raw model instances
+    result = await UserCrud.offset_paginate(session=session, page=1)
+    result = await UserCrud.cursor_paginate(session=session, cursor=token)
+    ```
+
+=== "Now (`v2`)"
+
+    ```python
+    result = await UserCrud.offset_paginate(session=session, page=1, schema=UserRead)
+    result = await UserCrud.cursor_paginate(session=session, cursor=token, schema=UserRead)
+    ```
+
+### `as_response` removed from `create()`, `get()`, and `update()`
+
+Passing `as_response` to these methods will raise a `TypeError` at runtime.
+
+The `as_response=True` shorthand is replaced by passing a `schema` directly. The return value is a `Response[schema]` when `schema` is provided, or the raw model instance when it is not.
+
+=== "Before (`v1`)"
+
+    ```python
+    user = await UserCrud.create(session=session, obj=data, as_response=True)
+    user = await UserCrud.get(session=session, filters=filters, as_response=True)
+    user = await UserCrud.update(session=session, obj=data, filters, as_response=True)
+    ```
+
+=== "Now (`v2`)"
+
+    ```python
+    user = await UserCrud.create(session=session, obj=data, schema=UserRead)
+    user = await UserCrud.get(session=session, filters=filters, schema=UserRead)
+    user = await UserCrud.update(session=session, obj=data, filters, schema=UserRead)
+    ```
+
+### `delete()`: `as_response` renamed and return type changed
+
+`as_response` is gone, and the plain (non-response) call no longer returns `True`.
+
+Two changes were made to `delete()`:
+
+1. The `as_response` parameter is renamed to `return_response`.
+2. When called without `return_response=True`, the method now returns `None` on success instead of `True`.
+
+=== "Before (`v1`)"
+
+    ```python
+    ok = await UserCrud.delete(session=session, filters=filters)
+    if ok:  # True on success
+        ...
+
+    response = await UserCrud.delete(session=session, filters=filters, as_response=True)
+    ```
+
+=== "Now (`v2`)"
+
+    ```python
+    await UserCrud.delete(session=session, filters=filters)  # returns None
+
+    response = await UserCrud.delete(session=session, filters=filters, return_response=True)
+    ```
+
+### `paginate()` alias removed
+
+Any call to `crud.paginate(...)` will raise `AttributeError` at runtime.
+
+The `paginate` shorthand was an alias for `offset_paginate`. It has been removed; call `offset_paginate` directly.
+
+=== "Before (`v1`)"
+
+    ```python
+    result = await UserCrud.paginate(session=session, page=2, items_per_page=20, schema=UserRead)
+    ```
+
+=== "Now (`v2`)"
+
+    ```python
+    result = await UserCrud.offset_paginate(session=session, page=2, items_per_page=20, schema=UserRead)
+    ```
+
+---
+
+## Exceptions
+
+### Missing `api_error` raises `TypeError` at class definition time
+
+Unfinished or stub exception subclasses that previously compiled fine will now fail on import.
+
+In `v1`, a subclass without `api_error` would only fail when the exception was raised. In `v2`, `__init_subclass__` validates this at class definition time.
+
+=== "Before (`v1`)"
+
+    ```python
+    class MyError(ApiException):
+        pass  # fine until raised
+    ```
+
+=== "Now (`v2`)"
+
+    ```python
+    class MyError(ApiException):
+        pass  # TypeError: MyError must define an 'api_error' class attribute.
+    ```
+
+For shared base classes that are not meant to be raised directly, use `abstract=True`:
+
+```python
+class BillingError(ApiException, abstract=True):
+    """Base for all billing-related errors — not raised directly."""
+
+class PaymentRequiredError(BillingError):
+    api_error = ApiError(code=402, msg="Payment Required", desc="...", err_code="BILLING-402")
+```
+
+---
+
+## Schemas
+
+### `Pagination` alias removed
+
+`Pagination` was already deprecated in `v1` and is fully removed in `v2`, you now need to use [`OffsetPagination`](../reference/schemas.md#fastapi_toolsets.schemas.OffsetPagination) or [`CursorPagination`](../reference/schemas.md#fastapi_toolsets.schemas.CursorPagination).

docs/module/crud.md

@@ -292,6 +292,8 @@ Use `filter_by` to pass the client's chosen filter values directly — no need t
 Use [`filter_params()`](../reference/crud.md#fastapi_toolsets.crud.factory.AsyncCrud.filter_params) to generate a dict with the facet filter values from the query parameters:
 
 ```python
+from typing import Annotated
+
 from fastapi import Depends
 
 UserCrud = CrudFactory(
@@ -303,7 +305,7 @@ UserCrud = CrudFactory(
 async def list_users(
     session: SessionDep,
     page: int = 1,
-    filter_by: dict[str, list[str]] = Depends(UserCrud.filter_params()),
+    filter_by: Annotated[dict[str, list[str]], Depends(UserCrud.filter_params())],
 ) -> PaginatedResponse[UserRead]:
     return await UserCrud.offset_paginate(
         session=session,
@@ -320,6 +322,58 @@ GET /users?status=active&country=FR   → filter_by={"status": ["active"], "coun
 GET /users?role=admin&role=editor     → filter_by={"role": ["admin", "editor"]}  (IN clause)
 ```
 
+## Sorting
+
+!!! info "Added in `v1.3`"
+
+Declare `order_fields` on the CRUD class to expose client-driven column ordering via `order_by` and `order` query parameters.
+
+```python
+UserCrud = CrudFactory(
+    model=User,
+    order_fields=[
+        User.name,
+        User.created_at,
+    ],
+)
+```
+
+Call [`order_params()`](../reference/crud.md#fastapi_toolsets.crud.factory.AsyncCrud.order_params) to generate a FastAPI dependency that maps the query parameters to an [`OrderByClause`](../reference/crud.md#fastapi_toolsets.crud.factory.OrderByClause) expression:
+
+```python
+from typing import Annotated
+
+from fastapi import Depends
+from fastapi_toolsets.crud import OrderByClause
+
+@router.get("")
+async def list_users(
+    session: SessionDep,
+    order_by: Annotated[OrderByClause | None, Depends(UserCrud.order_params())],
+) -> PaginatedResponse[UserRead]:
+    return await UserCrud.offset_paginate(session=session, order_by=order_by)
+```
+
+The dependency adds two query parameters to the endpoint:
+
+| Parameter  | Type            |
+| ---------- | --------------- |
+| `order_by` | `str | null`   |
+| `order`    | `asc` or `desc` |
+
+```
+GET /users?order_by=name&order=asc   → ORDER BY users.name ASC
+GET /users?order_by=name&order=desc  → ORDER BY users.name DESC
+```
+
+An unknown `order_by` value raises [`InvalidOrderFieldError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.InvalidOrderFieldError) (HTTP 422).
+
+You can also pass `order_fields` directly to `order_params()` to override the class-level defaults without modifying them:
+
+```python
+UserOrderParams = UserCrud.order_params(order_fields=[User.name])
+```
+
 ## Relationship loading
 
 !!! info "Added in `v1.1`"

docs/module/exceptions.md

@@ -21,30 +21,37 @@ init_exceptions_handlers(app=app)
 This registers handlers for:
 
 - [`ApiException`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.ApiException) — all custom exceptions below
+- `HTTPException` — Starlette/FastAPI HTTP errors
 - `RequestValidationError` — Pydantic request validation (422)
 - `ResponseValidationError` — Pydantic response validation (422)
 - `Exception` — unhandled errors (500)
 
+It also patches `app.openapi()` to replace the default Pydantic 422 schema with a structured example matching the `ErrorResponse` format.
+
 ## Built-in exceptions
 
 | Exception | Status | Default message |
 |-----------|--------|-----------------|
 | [`UnauthorizedError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.UnauthorizedError) | 401 | Unauthorized |
 | [`ForbiddenError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.ForbiddenError) | 403 | Forbidden |
-| [`NotFoundError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.NotFoundError) | 404 | Not found |
+| [`NotFoundError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.NotFoundError) | 404 | Not Found |
 | [`ConflictError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.ConflictError) | 409 | Conflict |
-| [`NoSearchableFieldsError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.NoSearchableFieldsError) | 400 | No searchable fields |
-| [`InvalidFacetFilterError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.InvalidFacetFilterError) | 400 | Invalid facet filter |
+| [`NoSearchableFieldsError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.NoSearchableFieldsError) | 400 | No Searchable Fields |
+| [`InvalidFacetFilterError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.InvalidFacetFilterError) | 400 | Invalid Facet Filter |
+| [`InvalidOrderFieldError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.InvalidOrderFieldError) | 422 | Invalid Order Field |
+
+### Per-instance overrides
+
+All built-in exceptions accept optional keyword arguments to customise the response for a specific raise site without changing the class defaults:
+
+| Argument | Effect |
+|----------|--------|
+| `detail` | Overrides both `str(exc)` (log output) and the `message` field in the response body |
+| `desc` | Overrides the `description` field |
+| `data` | Overrides the `data` field |
 
 ```python
-from fastapi_toolsets.exceptions import NotFoundError
-
-@router.get("/users/{id}")
-async def get_user(id: int, session: AsyncSession = Depends(get_db)):
-    user = await UserCrud.first(session=session, filters=[User.id == id])
-    if not user:
-        raise NotFoundError
-    return user
+raise NotFoundError(detail="User 42 not found", desc="No user with that ID exists in the database.")
 ```
 
 ## Custom exceptions
@@ -58,12 +65,51 @@ from fastapi_toolsets.schemas import ApiError
 class PaymentRequiredError(ApiException):
     api_error = ApiError(
         code=402,
-        msg="Payment required",
+        msg="Payment Required",
         desc="Your subscription has expired.",
-        err_code="PAYMENT_REQUIRED",
+        err_code="BILLING-402",
     )
 ```
 
+!!! warning
+    Subclasses that do not define `api_error` raise a `TypeError` at **class creation time**, not at raise time.
+
+### Custom `__init__`
+
+Override `__init__` to compute `detail`, `desc`, or `data` dynamically, then delegate to `super().__init__()`:
+
+```python
+class OrderValidationError(ApiException):
+    api_error = ApiError(
+        code=422,
+        msg="Order Validation Failed",
+        desc="One or more order fields are invalid.",
+        err_code="ORDER-422",
+    )
+
+    def __init__(self, *field_errors: str) -> None:
+        super().__init__(
+            f"{len(field_errors)} validation error(s)",
+            desc=", ".join(field_errors),
+            data={"errors": [{"message": e} for e in field_errors]},
+        )
+```
+
+### Intermediate base classes
+
+Use `abstract=True` when creating a shared base that is not meant to be raised directly:
+
+```python
+class BillingError(ApiException, abstract=True):
+    """Base for all billing-related errors."""
+
+class PaymentRequiredError(BillingError):
+    api_error = ApiError(code=402, msg="Payment Required", desc="...", err_code="BILLING-402")
+
+class SubscriptionExpiredError(BillingError):
+    api_error = ApiError(code=402, msg="Subscription Expired", desc="...", err_code="BILLING-402-EXP")
+```
+
 ## OpenAPI response documentation
 
 Use [`generate_error_responses`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.generate_error_responses) to add error schemas to your endpoint's OpenAPI spec:
@@ -78,8 +124,7 @@ from fastapi_toolsets.exceptions import generate_error_responses, NotFoundError,
 async def get_user(...): ...
 ```
 
-!!! info
-    The pydantic validation error is automatically added by FastAPI.
+Multiple exceptions sharing the same HTTP status code are grouped under one entry, each appearing as a named example keyed by its `err_code`. This keeps the OpenAPI UI readable when several error variants map to the same status.
 
 ---
 

docs/module/models.md

@@ -0,0 +1,113 @@
+# Models
+
+!!! info "Added in `v2.0`"
+
+Reusable SQLAlchemy 2.0 mixins for common column patterns, designed to be composed freely on any `DeclarativeBase` model.
+
+## Overview
+
+The `models` module provides mixins that each add a single, well-defined column behaviour. They work with standard SQLAlchemy 2.0 declarative syntax and are fully compatible with `AsyncSession`.
+
+```python
+from fastapi_toolsets.models import UUIDMixin, TimestampMixin
+
+class Article(Base, UUIDMixin, TimestampMixin):
+    __tablename__ = "articles"
+
+    title: Mapped[str]
+    content: Mapped[str]
+```
+
+All timestamp columns are timezone-aware (`TIMESTAMPTZ`). All defaults are server-side, so they are also applied when inserting rows via raw SQL outside the ORM.
+
+## Mixins
+
+### [`UUIDMixin`](../reference/models.md#fastapi_toolsets.models.UUIDMixin)
+
+Adds a `id: UUID` primary key generated server-side by PostgreSQL using `gen_random_uuid()` (requires PostgreSQL 13+). The value is retrieved via `RETURNING` after insert, so it is available on the Python object immediately after `flush()`.
+
+```python
+from fastapi_toolsets.models import UUIDMixin
+
+class User(Base, UUIDMixin):
+    __tablename__ = "users"
+
+    username: Mapped[str]
+
+# id is None before flush
+user = User(username="alice")
+await session.flush()
+print(user.id)  # UUID('...')
+```
+
+### [`CreatedAtMixin`](../reference/models.md#fastapi_toolsets.models.CreatedAtMixin)
+
+Adds a `created_at: datetime` column set to `NOW()` on insert. The column has no `onupdate` hook — it is intentionally immutable after the row is created.
+
+```python
+from fastapi_toolsets.models import UUIDMixin, CreatedAtMixin
+
+class Order(Base, UUIDMixin, CreatedAtMixin):
+    __tablename__ = "orders"
+
+    total: Mapped[float]
+```
+
+### [`UpdatedAtMixin`](../reference/models.md#fastapi_toolsets.models.UpdatedAtMixin)
+
+Adds an `updated_at: datetime` column set to `NOW()` on insert and automatically updated to `NOW()` on every ORM-level update (via SQLAlchemy's `onupdate` hook).
+
+```python
+from fastapi_toolsets.models import UUIDMixin, UpdatedAtMixin
+
+class Post(Base, UUIDMixin, UpdatedAtMixin):
+    __tablename__ = "posts"
+
+    title: Mapped[str]
+
+post = Post(title="Hello")
+await session.flush()
+await session.refresh(post)
+
+post.title = "Hello World"
+await session.flush()
+await session.refresh(post)
+print(post.updated_at)
+```
+
+!!! note
+    `updated_at` is updated by SQLAlchemy at ORM flush time. If you update rows via raw SQL (e.g. `UPDATE posts SET ...`), the column will **not** be updated automatically — use a database trigger if you need that guarantee.
+
+### [`TimestampMixin`](../reference/models.md#fastapi_toolsets.models.TimestampMixin)
+
+Convenience mixin that combines [`CreatedAtMixin`](../reference/models.md#fastapi_toolsets.models.CreatedAtMixin) and [`UpdatedAtMixin`](../reference/models.md#fastapi_toolsets.models.UpdatedAtMixin). Equivalent to inheriting both.
+
+```python
+from fastapi_toolsets.models import UUIDMixin, TimestampMixin
+
+class Article(Base, UUIDMixin, TimestampMixin):
+    __tablename__ = "articles"
+
+    title: Mapped[str]
+```
+
+## Composing mixins
+
+All mixins can be combined in any order. The only constraint is that exactly one primary key must be defined — either via `UUIDMixin` or directly on the model.
+
+```python
+from fastapi_toolsets.models import UUIDMixin, TimestampMixin
+
+class Event(Base, UUIDMixin, TimestampMixin):
+    __tablename__ = "events"
+    name: Mapped[str]
+
+class Counter(Base, UpdatedAtMixin):
+    __tablename__ = "counters"
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    value: Mapped[int]
+```
+
+---
+
+[:material-api: API Reference](../reference/models.md)

docs/module/schemas.md

@@ -22,16 +22,20 @@ async def get_user(user: User = UserDep) -> Response[UserSchema]:
 
 ### [`PaginatedResponse[T]`](../reference/schemas.md#fastapi_toolsets.schemas.PaginatedResponse)
 
-Wraps a list of items with pagination metadata and optional facet values.
+Wraps a list of items with pagination metadata and optional facet values. The `pagination` field accepts either [`OffsetPagination`](../reference/schemas.md#fastapi_toolsets.schemas.OffsetPagination) or [`CursorPagination`](../reference/schemas.md#fastapi_toolsets.schemas.CursorPagination) depending on the strategy used.
+
+#### [`OffsetPagination`](../reference/schemas.md#fastapi_toolsets.schemas.OffsetPagination)
+
+Page-number based. Requires `total_count` so clients can compute the total number of pages.
 
 ```python
-from fastapi_toolsets.schemas import PaginatedResponse, Pagination
+from fastapi_toolsets.schemas import PaginatedResponse, OffsetPagination
 
 @router.get("/users")
 async def list_users() -> PaginatedResponse[UserSchema]:
     return PaginatedResponse(
         data=users,
-        pagination=Pagination(
+        pagination=OffsetPagination(
             total_count=100,
             items_per_page=10,
             page=1,
@@ -40,6 +44,26 @@ async def list_users() -> PaginatedResponse[UserSchema]:
     )
 ```
 
+#### [`CursorPagination`](../reference/schemas.md#fastapi_toolsets.schemas.CursorPagination)
+
+Cursor based. Efficient for large or frequently updated datasets where offset pagination is impractical. Provides opaque `next_cursor` / `prev_cursor` tokens; no total count is exposed.
+
+```python
+from fastapi_toolsets.schemas import PaginatedResponse, CursorPagination
+
+@router.get("/events")
+async def list_events() -> PaginatedResponse[EventSchema]:
+    return PaginatedResponse(
+        data=events,
+        pagination=CursorPagination(
+            next_cursor="eyJpZCI6IDQyfQ==",
+            prev_cursor=None,
+            items_per_page=20,
+            has_more=True,
+        ),
+    )
+```
+
 The optional `filter_attributes` field is populated when `facet_fields` are configured on the CRUD class (see [Filter attributes](crud.md#filter-attributes-facets)). It is `None` by default and can be hidden from API responses with `response_model_exclude_none=True`.
 
 ### [`ErrorResponse`](../reference/schemas.md#fastapi_toolsets.schemas.ErrorResponse)

docs/reference/exceptions.md

@@ -13,6 +13,7 @@ from fastapi_toolsets.exceptions import (
     ConflictError,
     NoSearchableFieldsError,
     InvalidFacetFilterError,
+    InvalidOrderFieldError,
     generate_error_responses,
     init_exceptions_handlers,
 )
@@ -32,6 +33,8 @@ from fastapi_toolsets.exceptions import (
 
 ## ::: fastapi_toolsets.exceptions.exceptions.InvalidFacetFilterError
 
+## ::: fastapi_toolsets.exceptions.exceptions.InvalidOrderFieldError
+
 ## ::: fastapi_toolsets.exceptions.exceptions.generate_error_responses
 
 ## ::: fastapi_toolsets.exceptions.handler.init_exceptions_handlers

docs/reference/models.md

@@ -0,0 +1,22 @@
+# `models`
+
+Here's the reference for the SQLAlchemy model mixins provided by the `models` module.
+
+You can import them directly from `fastapi_toolsets.models`:
+
+```python
+from fastapi_toolsets.models import (
+    UUIDMixin,
+    CreatedAtMixin,
+    UpdatedAtMixin,
+    TimestampMixin,
+)
+```
+
+## ::: fastapi_toolsets.models.UUIDMixin
+
+## ::: fastapi_toolsets.models.CreatedAtMixin
+
+## ::: fastapi_toolsets.models.UpdatedAtMixin
+
+## ::: fastapi_toolsets.models.TimestampMixin

docs/reference/schemas.md

@@ -1,4 +1,4 @@
-# `schemas` module
+# `schemas`
 
 Here's the reference for all response models and types provided by the `schemas` module.
 
@@ -12,7 +12,8 @@ from fastapi_toolsets.schemas import (
     BaseResponse,
     Response,
     ErrorResponse,
-    Pagination,
+    OffsetPagination,
+    CursorPagination,
     PaginatedResponse,
 )
 ```
@@ -29,6 +30,8 @@ from fastapi_toolsets.schemas import (
 
 ## ::: fastapi_toolsets.schemas.ErrorResponse
 
-## ::: fastapi_toolsets.schemas.Pagination
+## ::: fastapi_toolsets.schemas.OffsetPagination
+
+## ::: fastapi_toolsets.schemas.CursorPagination
 
 ## ::: fastapi_toolsets.schemas.PaginatedResponse

docs_src/examples/pagination_search/app.py

@@ -1,6 +1,9 @@
 from fastapi import FastAPI
 
+from fastapi_toolsets.exceptions import init_exceptions_handlers
+
 from .routes import router
 
 app = FastAPI()
+init_exceptions_handlers(app=app)
 app.include_router(router=router)

docs_src/examples/pagination_search/crud.py

@@ -14,6 +14,8 @@ ArticleCrud = CrudFactory(
         Article.status,
         (Article.category, Category.name),
     ],
+    order_fields=[  # fields exposed for client-driven ordering
+        Article.title,
+        Article.created_at,
+    ],
 )
-
-ArticleFilters = ArticleCrud.filter_params()

docs_src/examples/pagination_search/routes.py

@@ -1,9 +1,13 @@
+from typing import Annotated
+
 from fastapi import APIRouter, Depends, Query
 
+from fastapi_toolsets.crud import OrderByClause
 from fastapi_toolsets.schemas import PaginatedResponse
 
 from .crud import ArticleCrud
 from .db import SessionDep
+from .models import Article
 from .schemas import ArticleRead
 
 router = APIRouter(prefix="/articles")
@@ -12,10 +16,14 @@ router = APIRouter(prefix="/articles")
 @router.get("/offset")
 async def list_articles_offset(
     session: SessionDep,
+    filter_by: Annotated[dict[str, list[str]], Depends(ArticleCrud.filter_params())],
+    order_by: Annotated[
+        OrderByClause | None,
+        Depends(ArticleCrud.order_params(default_field=Article.created_at)),
+    ],
     page: int = Query(1, ge=1),
     items_per_page: int = Query(20, ge=1, le=100),
     search: str | None = None,
-    filter_by: dict[str, list[str]] = Depends(ArticleCrud.filter_params()),
 ) -> PaginatedResponse[ArticleRead]:
     return await ArticleCrud.offset_paginate(
         session=session,
@@ -23,6 +31,7 @@ async def list_articles_offset(
         items_per_page=items_per_page,
         search=search,
         filter_by=filter_by or None,
+        order_by=order_by,
         schema=ArticleRead,
     )
 
@@ -30,10 +39,14 @@ async def list_articles_offset(
 @router.get("/cursor")
 async def list_articles_cursor(
     session: SessionDep,
+    filter_by: Annotated[dict[str, list[str]], Depends(ArticleCrud.filter_params())],
+    order_by: Annotated[
+        OrderByClause | None,
+        Depends(ArticleCrud.order_params(default_field=Article.created_at)),
+    ],
     cursor: str | None = None,
     items_per_page: int = Query(20, ge=1, le=100),
     search: str | None = None,
-    filter_by: dict[str, list[str]] = Depends(ArticleCrud.filter_params()),
 ) -> PaginatedResponse[ArticleRead]:
     return await ArticleCrud.cursor_paginate(
         session=session,
@@ -41,5 +54,6 @@ async def list_articles_cursor(
         items_per_page=items_per_page,
         search=search,
         filter_by=filter_by or None,
+        order_by=order_by,
         schema=ArticleRead,
     )

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "fastapi-toolsets"
-version = "1.2.1"
+version = "2.0.0"
 description = "Production-ready utilities for FastAPI applications"
 readme = "README.md"
 license = "MIT"

src/fastapi_toolsets/__init__.py

@@ -21,4 +21,4 @@ Example usage:
         return Response(data={"user": user.username}, message="Success")
 """
 
-__version__ = "1.2.1"
+__version__ = "2.0.0"

src/fastapi_toolsets/cli/commands/fixtures.py

@@ -72,7 +72,7 @@ async def load(
     registry = get_fixtures_registry()
     db_context = get_db_context()
 
-    context_list = [c.value for c in contexts] if contexts else [Context.BASE]
+    context_list = list(contexts) if contexts else [Context.BASE]
 
     ordered = registry.resolve_context_dependencies(*context_list)
 

src/fastapi_toolsets/crud/__init__.py

@@ -1,12 +1,15 @@
 """Generic async CRUD operations for SQLAlchemy models."""
 
 from ..exceptions import InvalidFacetFilterError, NoSearchableFieldsError
-from .factory import CrudFactory, JoinType, M2MFieldType
-from .search import (
+from ..types import (
     FacetFieldType,
-    SearchConfig,
-    get_searchable_fields,
+    JoinType,
+    M2MFieldType,
+    OrderByClause,
+    SearchFieldType,
 )
+from .factory import CrudFactory
+from .search import SearchConfig, get_searchable_fields
 
 __all__ = [
     "CrudFactory",
@@ -16,5 +19,7 @@ __all__ = [
     "JoinType",
     "M2MFieldType",
     "NoSearchableFieldsError",
+    "OrderByClause",
     "SearchConfig",
+    "SearchFieldType",
 ]

src/fastapi_toolsets/crud/factory.py

@@ -6,10 +6,10 @@ import base64
 import inspect
 import json
 import uuid as uuid_module
-from collections.abc import Awaitable, Callable, Mapping, Sequence
+from collections.abc import Awaitable, Callable, Sequence
 from datetime import date, datetime
 from decimal import Decimal
-from typing import Any, ClassVar, Generic, Literal, Self, TypeVar, cast, overload
+from typing import Any, ClassVar, Generic, Literal, Self, cast, overload
 
 from fastapi import Query
 from pydantic import BaseModel
@@ -23,23 +23,25 @@ from sqlalchemy.sql.base import ExecutableOption
 from sqlalchemy.sql.roles import WhereHavingRole
 
 from ..db import get_transaction
-from ..exceptions import NotFoundError
+from ..exceptions import InvalidOrderFieldError, NotFoundError
 from ..schemas import CursorPagination, OffsetPagination, PaginatedResponse, Response
-from .search import (
+from ..types import (
     FacetFieldType,
-    SearchConfig,
+    JoinType,
+    M2MFieldType,
+    ModelType,
+    OrderByClause,
+    SchemaType,
     SearchFieldType,
+)
+from .search import (
+    SearchConfig,
     build_facets,
     build_filter_by,
     build_search_filters,
     facet_keys,
 )
 
-ModelType = TypeVar("ModelType", bound=DeclarativeBase)
-SchemaType = TypeVar("SchemaType", bound=BaseModel)
-JoinType = list[tuple[type[DeclarativeBase], Any]]
-M2MFieldType = Mapping[str, QueryableAttribute[Any]]
-
 
 def _encode_cursor(value: Any) -> str:
     """Encode cursor column value as an base64 string."""
@@ -51,6 +53,22 @@ def _decode_cursor(cursor: str) -> str:
     return json.loads(base64.b64decode(cursor.encode()).decode())
 
 
+def _apply_joins(q: Any, joins: JoinType | None, outer_join: bool) -> Any:
+    """Apply a list of (model, condition) joins to a SQLAlchemy select query."""
+    if not joins:
+        return q
+    for model, condition in joins:
+        q = q.outerjoin(model, condition) if outer_join else q.join(model, condition)
+    return q
+
+
+def _apply_search_joins(q: Any, search_joins: list[Any]) -> Any:
+    """Apply relationship-based outer joins (from search/filter_by) to a query."""
+    for join_rel in search_joins:
+        q = q.outerjoin(join_rel)
+    return q
+
+
 class AsyncCrud(Generic[ModelType]):
     """Generic async CRUD operations for SQLAlchemy models.
 
@@ -60,6 +78,7 @@ class AsyncCrud(Generic[ModelType]):
     model: ClassVar[type[DeclarativeBase]]
     searchable_fields: ClassVar[Sequence[SearchFieldType] | None] = None
     facet_fields: ClassVar[Sequence[FacetFieldType] | None] = None
+    order_fields: ClassVar[Sequence[QueryableAttribute[Any]] | None] = None
     m2m_fields: ClassVar[M2MFieldType | None] = None
     default_load_options: ClassVar[list[ExecutableOption] | None] = None
     cursor_column: ClassVar[Any | None] = None
@@ -129,6 +148,48 @@ class AsyncCrud(Generic[ModelType]):
             return set()
         return set(cls.m2m_fields.keys())
 
+    @classmethod
+    def _resolve_facet_fields(
+        cls: type[Self],
+        facet_fields: Sequence[FacetFieldType] | None,
+    ) -> Sequence[FacetFieldType] | None:
+        """Return facet_fields if given, otherwise fall back to the class-level default."""
+        return facet_fields if facet_fields is not None else cls.facet_fields
+
+    @classmethod
+    def _prepare_filter_by(
+        cls: type[Self],
+        filter_by: dict[str, Any] | BaseModel | None,
+        facet_fields: Sequence[FacetFieldType] | None,
+    ) -> tuple[list[Any], list[Any]]:
+        """Normalize filter_by and return (filters, joins) to apply to the query."""
+        if isinstance(filter_by, BaseModel):
+            filter_by = filter_by.model_dump(exclude_none=True)
+        if not filter_by:
+            return [], []
+        resolved = cls._resolve_facet_fields(facet_fields)
+        return build_filter_by(filter_by, resolved or [])
+
+    @classmethod
+    async def _build_filter_attributes(
+        cls: type[Self],
+        session: AsyncSession,
+        facet_fields: Sequence[FacetFieldType] | None,
+        filters: list[Any],
+        search_joins: list[Any],
+    ) -> dict[str, list[Any]] | None:
+        """Build facet filter_attributes, or return None if no facet fields configured."""
+        resolved = cls._resolve_facet_fields(facet_fields)
+        if not resolved:
+            return None
+        return await build_facets(
+            session,
+            cls.model,
+            resolved,
+            base_filters=filters,
+            base_joins=search_joins,
+        )
+
     @classmethod
     def filter_params(
         cls: type[Self],
@@ -149,7 +210,7 @@ class AsyncCrud(Generic[ModelType]):
             ValueError: If no facet fields are configured on this CRUD class and none are
                 provided via ``facet_fields``.
         """
-        fields = facet_fields if facet_fields is not None else cls.facet_fields
+        fields = cls._resolve_facet_fields(facet_fields)
         if not fields:
             raise ValueError(
                 f"{cls.__name__} has no facet_fields configured. "
@@ -175,6 +236,63 @@ class AsyncCrud(Generic[ModelType]):
 
         return dependency
 
+    @classmethod
+    def order_params(
+        cls: type[Self],
+        *,
+        order_fields: Sequence[QueryableAttribute[Any]] | None = None,
+        default_field: QueryableAttribute[Any] | None = None,
+        default_order: Literal["asc", "desc"] = "asc",
+    ) -> Callable[..., Awaitable[OrderByClause | None]]:
+        """Return a FastAPI dependency that resolves order query params into an order_by clause.
+
+        Args:
+            order_fields: Override the allowed order fields. Falls back to the class-level
+                ``order_fields`` if not provided.
+            default_field: Field to order by when ``order_by`` query param is absent.
+                If ``None`` and no ``order_by`` is provided, no ordering is applied.
+            default_order: Default order direction when ``order`` is absent
+                (``"asc"`` or ``"desc"``).
+
+        Returns:
+            An async dependency function named ``{Model}OrderParams`` that resolves to an
+            ``OrderByClause`` (or ``None``). Pass it to ``Depends()`` in your route.
+
+        Raises:
+            ValueError: If no order fields are configured on this CRUD class and none are
+                provided via ``order_fields``.
+            InvalidOrderFieldError: When the request provides an unknown ``order_by`` value.
+        """
+        fields = order_fields if order_fields is not None else cls.order_fields
+        if not fields:
+            raise ValueError(
+                f"{cls.__name__} has no order_fields configured. "
+                "Pass order_fields= or set them on CrudFactory."
+            )
+        field_map: dict[str, QueryableAttribute[Any]] = {f.key: f for f in fields}
+        valid_keys = sorted(field_map.keys())
+
+        async def dependency(
+            order_by: str | None = Query(
+                None, description=f"Field to order by. Valid values: {valid_keys}"
+            ),
+            order: Literal["asc", "desc"] = Query(
+                default_order, description="Sort direction"
+            ),
+        ) -> OrderByClause | None:
+            if order_by is None:
+                if default_field is None:
+                    return None
+                field = default_field
+            elif order_by not in field_map:
+                raise InvalidOrderFieldError(order_by, valid_keys)
+            else:
+                field = field_map[order_by]
+            return field.asc() if order == "asc" else field.desc()
+
+        dependency.__name__ = f"{cls.model.__name__}OrderParams"
+        return dependency
+
     @overload
     @classmethod
     async def create(  # pragma: no cover
@@ -230,8 +348,7 @@ class AsyncCrud(Generic[ModelType]):
         await session.refresh(db_model)
         result = cast(ModelType, db_model)
         if schema:
-            data_out = schema.model_validate(result) if schema else result
-            return Response(data=data_out)
+            return Response(data=schema.model_validate(result))
         return result
 
     @overload
@@ -294,13 +411,7 @@ class AsyncCrud(Generic[ModelType]):
             MultipleResultsFound: If more than one record found
         """
         q = select(cls.model)
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
         q = q.where(and_(*filters))
         if resolved := cls._resolve_load_options(load_options):
             q = q.options(*resolved)
@@ -312,8 +423,7 @@ class AsyncCrud(Generic[ModelType]):
             raise NotFoundError()
         result = cast(ModelType, item)
         if schema:
-            data_out = schema.model_validate(result) if schema else result
-            return Response(data=data_out)
+            return Response(data=schema.model_validate(result))
         return result
 
     @classmethod
@@ -339,13 +449,7 @@ class AsyncCrud(Generic[ModelType]):
             Model instance or None
         """
         q = select(cls.model)
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
         if filters:
             q = q.where(and_(*filters))
         if resolved := cls._resolve_load_options(load_options):
@@ -362,7 +466,7 @@ class AsyncCrud(Generic[ModelType]):
         joins: JoinType | None = None,
         outer_join: bool = False,
         load_options: list[ExecutableOption] | None = None,
-        order_by: Any | None = None,
+        order_by: OrderByClause | None = None,
         limit: int | None = None,
         offset: int | None = None,
     ) -> Sequence[ModelType]:
@@ -382,13 +486,7 @@ class AsyncCrud(Generic[ModelType]):
             List of model instances
         """
         q = select(cls.model)
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
         if filters:
             q = q.where(and_(*filters))
         if resolved := cls._resolve_load_options(load_options):
@@ -486,8 +584,7 @@ class AsyncCrud(Generic[ModelType]):
                     setattr(db_model, rel_attr, related_instances)
         await session.refresh(db_model)
         if schema:
-            data_out = schema.model_validate(db_model) if schema else db_model
-            return Response(data=data_out)
+            return Response(data=schema.model_validate(db_model))
         return db_model
 
     @classmethod
@@ -604,13 +701,7 @@ class AsyncCrud(Generic[ModelType]):
             Number of matching records
         """
         q = select(func.count()).select_from(cls.model)
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
         if filters:
             q = q.where(and_(*filters))
         result = await session.execute(q)
@@ -637,13 +728,7 @@ class AsyncCrud(Generic[ModelType]):
             True if at least one record matches
         """
         q = select(cls.model)
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
         q = q.where(and_(*filters)).exists().select()
         result = await session.execute(q)
         return bool(result.scalar())
@@ -657,7 +742,7 @@ class AsyncCrud(Generic[ModelType]):
         joins: JoinType | None = None,
         outer_join: bool = False,
         load_options: list[ExecutableOption] | None = None,
-        order_by: Any | None = None,
+        order_by: OrderByClause | None = None,
         page: int = 1,
         items_per_page: int = 20,
         search: str | SearchConfig | None = None,
@@ -690,47 +775,29 @@ class AsyncCrud(Generic[ModelType]):
         """
         filters = list(filters) if filters else []
         offset = (page - 1) * items_per_page
-        search_joins: list[Any] = []
 
-        if isinstance(filter_by, BaseModel):
-            filter_by = filter_by.model_dump(exclude_none=True) or None
-
-        # Build filter_by conditions from declared facet fields
-        if filter_by:
-            resolved_facets_for_filter = (
-                facet_fields if facet_fields is not None else cls.facet_fields
-            )
-            fb_filters, fb_joins = build_filter_by(
-                filter_by, resolved_facets_for_filter or []
-            )
-            filters.extend(fb_filters)
-            search_joins.extend(fb_joins)
+        fb_filters, search_joins = cls._prepare_filter_by(filter_by, facet_fields)
+        filters.extend(fb_filters)
 
         # Build search filters
         if search:
-            search_filters, search_joins = build_search_filters(
+            search_filters, new_search_joins = build_search_filters(
                 cls.model,
                 search,
                 search_fields=search_fields,
                 default_fields=cls.searchable_fields,
             )
             filters.extend(search_filters)
+            search_joins.extend(new_search_joins)
 
         # Build query with joins
         q = select(cls.model)
 
         # Apply explicit joins
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
 
         # Apply search joins (always outer joins for search)
-        for join_rel in search_joins:
-            q = q.outerjoin(join_rel)
+        q = _apply_search_joins(q, search_joins)
 
         if filters:
             q = q.where(and_(*filters))
@@ -750,17 +817,10 @@ class AsyncCrud(Generic[ModelType]):
         count_q = count_q.select_from(cls.model)
 
         # Apply explicit joins to count query
-        if joins:
-            for model, condition in joins:
-                count_q = (
-                    count_q.outerjoin(model, condition)
-                    if outer_join
-                    else count_q.join(model, condition)
-                )
+        count_q = _apply_joins(count_q, joins, outer_join)
 
         # Apply search joins to count query
-        for join_rel in search_joins:
-            count_q = count_q.outerjoin(join_rel)
+        count_q = _apply_search_joins(count_q, search_joins)
 
         if filters:
             count_q = count_q.where(and_(*filters))
@@ -768,19 +828,9 @@ class AsyncCrud(Generic[ModelType]):
         count_result = await session.execute(count_q)
         total_count = count_result.scalar_one()
 
-        # Build facets
-        resolved_facet_fields = (
-            facet_fields if facet_fields is not None else cls.facet_fields
+        filter_attributes = await cls._build_filter_attributes(
+            session, facet_fields, filters, search_joins
         )
-        filter_attributes: dict[str, list[Any]] | None = None
-        if resolved_facet_fields:
-            filter_attributes = await build_facets(
-                session,
-                cls.model,
-                resolved_facet_fields,
-                base_filters=filters or None,
-                base_joins=search_joins or None,
-            )
 
         return PaginatedResponse(
             data=items,
@@ -803,7 +853,7 @@ class AsyncCrud(Generic[ModelType]):
         joins: JoinType | None = None,
         outer_join: bool = False,
         load_options: list[ExecutableOption] | None = None,
-        order_by: Any | None = None,
+        order_by: OrderByClause | None = None,
         items_per_page: int = 20,
         search: str | SearchConfig | None = None,
         search_fields: Sequence[SearchFieldType] | None = None,
@@ -837,21 +887,9 @@ class AsyncCrud(Generic[ModelType]):
             PaginatedResponse with CursorPagination metadata
         """
         filters = list(filters) if filters else []
-        search_joins: list[Any] = []
 
-        if isinstance(filter_by, BaseModel):
-            filter_by = filter_by.model_dump(exclude_none=True) or None
-
-        # Build filter_by conditions from declared facet fields
-        if filter_by:
-            resolved_facets_for_filter = (
-                facet_fields if facet_fields is not None else cls.facet_fields
-            )
-            fb_filters, fb_joins = build_filter_by(
-                filter_by, resolved_facets_for_filter or []
-            )
-            filters.extend(fb_filters)
-            search_joins.extend(fb_joins)
+        fb_filters, search_joins = cls._prepare_filter_by(filter_by, facet_fields)
+        filters.extend(fb_filters)
 
         if cls.cursor_column is None:
             raise ValueError(
@@ -884,29 +922,23 @@ class AsyncCrud(Generic[ModelType]):
 
         # Build search filters
         if search:
-            search_filters, search_joins = build_search_filters(
+            search_filters, new_search_joins = build_search_filters(
                 cls.model,
                 search,
                 search_fields=search_fields,
                 default_fields=cls.searchable_fields,
             )
             filters.extend(search_filters)
+            search_joins.extend(new_search_joins)
 
         # Build query
         q = select(cls.model)
 
         # Apply explicit joins
-        if joins:
-            for model, condition in joins:
-                q = (
-                    q.outerjoin(model, condition)
-                    if outer_join
-                    else q.join(model, condition)
-                )
+        q = _apply_joins(q, joins, outer_join)
 
         # Apply search joins (always outer joins)
-        for join_rel in search_joins:
-            q = q.outerjoin(join_rel)
+        q = _apply_search_joins(q, search_joins)
 
         if filters:
             q = q.where(and_(*filters))
@@ -938,19 +970,9 @@ class AsyncCrud(Generic[ModelType]):
 
         items: list[Any] = [schema.model_validate(item) for item in items_page]
 
-        # Build facets
-        resolved_facet_fields = (
-            facet_fields if facet_fields is not None else cls.facet_fields
+        filter_attributes = await cls._build_filter_attributes(
+            session, facet_fields, filters, search_joins
         )
-        filter_attributes: dict[str, list[Any]] | None = None
-        if resolved_facet_fields:
-            filter_attributes = await build_facets(
-                session,
-                cls.model,
-                resolved_facet_fields,
-                base_filters=filters or None,
-                base_joins=search_joins or None,
-            )
 
         return PaginatedResponse(
             data=items,
@@ -969,6 +991,7 @@ def CrudFactory(
     *,
     searchable_fields: Sequence[SearchFieldType] | None = None,
     facet_fields: Sequence[FacetFieldType] | None = None,
+    order_fields: Sequence[QueryableAttribute[Any]] | None = None,
     m2m_fields: M2MFieldType | None = None,
     default_load_options: list[ExecutableOption] | None = None,
     cursor_column: Any | None = None,
@@ -981,6 +1004,8 @@ def CrudFactory(
         facet_fields: Optional list of columns to compute distinct values for in paginated
             responses. Supports direct columns (``User.status``) and relationship tuples
             (``(User.role, Role.name)``). Can be overridden per call.
+        order_fields: Optional list of model attributes that callers are allowed to order by
+            via ``order_params()``. Can be overridden per call.
         m2m_fields: Optional mapping for many-to-many relationships.
             Maps schema field names (containing lists of IDs) to
             SQLAlchemy relationship attributes.
@@ -1074,6 +1099,7 @@ def CrudFactory(
             "model": model,
             "searchable_fields": searchable_fields,
             "facet_fields": facet_fields,
+            "order_fields": order_fields,
             "m2m_fields": m2m_fields,
             "default_load_options": default_load_options,
             "cursor_column": cursor_column,

src/fastapi_toolsets/crud/search.py

@@ -1,24 +1,23 @@
 """Search utilities for AsyncCrud."""
 
 import asyncio
+import functools
 from collections import Counter
 from collections.abc import Sequence
-from dataclasses import dataclass
+from dataclasses import dataclass, replace
 from typing import TYPE_CHECKING, Any, Literal
 
-from sqlalchemy import String, or_, select
+from sqlalchemy import String, and_, or_, select
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import DeclarativeBase
 from sqlalchemy.orm.attributes import InstrumentedAttribute
 
 from ..exceptions import InvalidFacetFilterError, NoSearchableFieldsError
+from ..types import FacetFieldType, SearchFieldType
 
 if TYPE_CHECKING:
     from sqlalchemy.sql.elements import ColumnElement
 
-SearchFieldType = InstrumentedAttribute[Any] | tuple[InstrumentedAttribute[Any], ...]
-FacetFieldType = SearchFieldType
-
 
 @dataclass
 class SearchConfig:
@@ -37,6 +36,7 @@ class SearchConfig:
     match_mode: Literal["any", "all"] = "any"
 
 
+@functools.lru_cache(maxsize=128)
 def get_searchable_fields(
     model: type[DeclarativeBase],
     *,
@@ -101,14 +101,11 @@ def build_search_filters(
     if isinstance(search, str):
         config = SearchConfig(query=search, fields=search_fields)
     else:
-        config = search
-        if search_fields is not None:
-            config = SearchConfig(
-                query=config.query,
-                fields=search_fields,
-                case_sensitive=config.case_sensitive,
-                match_mode=config.match_mode,
-            )
+        config = (
+            replace(search, fields=search_fields)
+            if search_fields is not None
+            else search
+        )
 
     if not config.query or not config.query.strip():
         return [], []
@@ -227,8 +224,6 @@ async def build_facets(
                 q = q.outerjoin(rel)
 
         if base_filters:
-            from sqlalchemy import and_
-
             q = q.where(and_(*base_filters))
 
         q = q.order_by(column)

src/fastapi_toolsets/db.py

@@ -10,6 +10,8 @@ from sqlalchemy import text
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
 from sqlalchemy.orm import DeclarativeBase
 
+from .exceptions import NotFoundError
+
 __all__ = [
     "LockMode",
     "create_db_context",
@@ -216,7 +218,7 @@ async def wait_for_row_change(
         The refreshed model instance with updated values
 
     Raises:
-        LookupError: If the row does not exist or is deleted during polling
+        NotFoundError: If the row does not exist or is deleted during polling
         TimeoutError: If timeout expires before a change is detected
 
     Example:
@@ -237,7 +239,7 @@ async def wait_for_row_change(
     """
     instance = await session.get(model, pk_value)
     if instance is None:
-        raise LookupError(f"{model.__name__} with pk={pk_value!r} not found")
+        raise NotFoundError(f"{model.__name__} with pk={pk_value!r} not found")
 
     if columns is not None:
         watch_cols = columns
@@ -261,7 +263,7 @@ async def wait_for_row_change(
         instance = await session.get(model, pk_value)
 
         if instance is None:
-            raise LookupError(f"{model.__name__} with pk={pk_value!r} was deleted")
+            raise NotFoundError(f"{model.__name__} with pk={pk_value!r} was deleted")
 
         current = {col: getattr(instance, col) for col in watch_cols}
         if current != initial:

src/fastapi_toolsets/dependencies.py

@@ -1,20 +1,17 @@
 """Dependency factories for FastAPI routes."""
 
 import inspect
-from collections.abc import AsyncGenerator, Callable
-from typing import Any, TypeVar, cast
+from collections.abc import Callable
+from typing import Any, cast
 
 from fastapi import Depends
 from sqlalchemy.ext.asyncio import AsyncSession
-from sqlalchemy.orm import DeclarativeBase
 
 from .crud import CrudFactory
+from .types import ModelType, SessionDependency
 
 __all__ = ["BodyDependency", "PathDependency"]
 
-ModelType = TypeVar("ModelType", bound=DeclarativeBase)
-SessionDependency = Callable[[], AsyncGenerator[AsyncSession, None]]
-
 
 def PathDependency(
     model: type[ModelType],

src/fastapi_toolsets/exceptions/__init__.py

@@ -6,6 +6,7 @@ from .exceptions import (
     ConflictError,
     ForbiddenError,
     InvalidFacetFilterError,
+    InvalidOrderFieldError,
     NoSearchableFieldsError,
     NotFoundError,
     UnauthorizedError,
@@ -21,6 +22,7 @@ __all__ = [
     "generate_error_responses",
     "init_exceptions_handlers",
     "InvalidFacetFilterError",
+    "InvalidOrderFieldError",
     "NoSearchableFieldsError",
     "NotFoundError",
     "UnauthorizedError",

src/fastapi_toolsets/exceptions/exceptions.py

@@ -6,32 +6,46 @@ from ..schemas import ApiError, ErrorResponse, ResponseStatus
 
 
 class ApiException(Exception):
-    """Base exception for API errors with structured response.
-
-    Subclass this to create custom API exceptions with consistent error format.
-    The exception handler will use api_error to generate the response.
-
-    Example:
-        ```python
-        class CustomError(ApiException):
-            api_error = ApiError(
-                code=400,
-                msg="Bad Request",
-                desc="The request was invalid.",
-                err_code="CUSTOM-400",
-            )
-        ```
-    """
+    """Base exception for API errors with structured response."""
 
     api_error: ClassVar[ApiError]
 
-    def __init__(self, detail: str | None = None):
+    def __init_subclass__(cls, abstract: bool = False, **kwargs: Any) -> None:
+        super().__init_subclass__(**kwargs)
+        if not abstract and not hasattr(cls, "api_error"):
+            raise TypeError(
+                f"{cls.__name__} must define an 'api_error' class attribute. "
+                "Pass abstract=True when creating intermediate base classes."
+            )
+
+    def __init__(
+        self,
+        detail: str | None = None,
+        *,
+        desc: str | None = None,
+        data: Any = None,
+    ) -> None:
         """Initialize the exception.
 
         Args:
-            detail: Optional override for the error message
+            detail: Optional human-readable message
+            desc: Optional per-instance override for the ``description`` field
+                in the HTTP response body.
+            data: Optional per-instance override for the ``data`` field in the
+                HTTP response body.
         """
-        super().__init__(detail or self.api_error.msg)
+        updates: dict[str, Any] = {}
+        if detail is not None:
+            updates["msg"] = detail
+        if desc is not None:
+            updates["desc"] = desc
+        if data is not None:
+            updates["data"] = data
+        if updates:
+            object.__setattr__(
+                self, "api_error", self.__class__.api_error.model_copy(update=updates)
+            )
+        super().__init__(self.api_error.msg)
 
 
 class UnauthorizedError(ApiException):
@@ -92,14 +106,15 @@ class NoSearchableFieldsError(ApiException):
         """Initialize the exception.
 
         Args:
-            model: The SQLAlchemy model class that has no searchable fields
+            model: The model class that has no searchable fields configured.
         """
         self.model = model
-        detail = (
-            f"No searchable fields found for model '{model.__name__}'. "
-            "Provide 'search_fields' parameter or set 'searchable_fields' on the CRUD class."
+        super().__init__(
+            desc=(
+                f"No searchable fields found for model '{model.__name__}'. "
+                "Provide 'search_fields' parameter or set 'searchable_fields' on the CRUD class."
+            )
         )
-        super().__init__(detail)
 
 
 class InvalidFacetFilterError(ApiException):
@@ -116,16 +131,41 @@ class InvalidFacetFilterError(ApiException):
         """Initialize the exception.
 
         Args:
-            key: The unknown filter key provided by the caller
-            valid_keys: Set of valid keys derived from the declared facet_fields
+            key: The unknown filter key provided by the caller.
+            valid_keys: Set of valid keys derived from the declared facet_fields.
         """
         self.key = key
         self.valid_keys = valid_keys
-        detail = (
-            f"'{key}' is not a declared facet field. "
-            f"Valid keys: {sorted(valid_keys) or 'none — set facet_fields on the CRUD class'}."
+        super().__init__(
+            desc=(
+                f"'{key}' is not a declared facet field. "
+                f"Valid keys: {sorted(valid_keys) or 'none — set facet_fields on the CRUD class'}."
+            )
+        )
+
+
+class InvalidOrderFieldError(ApiException):
+    """Raised when order_by contains a field not in the allowed order fields."""
+
+    api_error = ApiError(
+        code=422,
+        msg="Invalid Order Field",
+        desc="The requested order field is not allowed for this resource.",
+        err_code="SORT-422",
+    )
+
+    def __init__(self, field: str, valid_fields: list[str]) -> None:
+        """Initialize the exception.
+
+        Args:
+            field: The unknown order field provided by the caller.
+            valid_fields: List of valid field names.
+        """
+        self.field = field
+        self.valid_fields = valid_fields
+        super().__init__(
+            desc=f"'{field}' is not an allowed order field. Valid fields: {valid_fields}."
         )
-        super().__init__(detail)
 
 
 def generate_error_responses(
@@ -133,44 +173,39 @@ def generate_error_responses(
 ) -> dict[int | str, dict[str, Any]]:
     """Generate OpenAPI response documentation for exceptions.
 
-    Use this to document possible error responses for an endpoint.
-
     Args:
-        *errors: Exception classes that inherit from ApiException
+        *errors: Exception classes that inherit from ApiException.
 
     Returns:
-        Dict suitable for FastAPI's responses parameter
-
-    Example:
-        ```python
-        from fastapi_toolsets.exceptions import generate_error_responses, UnauthorizedError, ForbiddenError
-
-        @app.get(
-            "/admin",
-            responses=generate_error_responses(UnauthorizedError, ForbiddenError)
-        )
-        async def admin_endpoint():
-            ...
-        ```
+        Dict suitable for FastAPI's ``responses`` parameter.
     """
     responses: dict[int | str, dict[str, Any]] = {}
 
     for error in errors:
         api_error = error.api_error
+        code = api_error.code
 
-        responses[api_error.code] = {
-            "model": ErrorResponse,
-            "description": api_error.msg,
-            "content": {
-                "application/json": {
-                    "example": {
-                        "data": api_error.data,
-                        "status": ResponseStatus.FAIL.value,
-                        "message": api_error.msg,
-                        "description": api_error.desc,
-                        "error_code": api_error.err_code,
+        if code not in responses:
+            responses[code] = {
+                "model": ErrorResponse,
+                "description": api_error.msg,
+                "content": {
+                    "application/json": {
+                        "examples": {},
                     }
-                }
+                },
+            }
+
+        responses[code]["content"]["application/json"]["examples"][
+            api_error.err_code
+        ] = {
+            "summary": api_error.msg,
+            "value": {
+                "data": api_error.data,
+                "status": ResponseStatus.FAIL.value,
+                "message": api_error.msg,
+                "description": api_error.desc,
+                "error_code": api_error.err_code,
             },
         }
 

src/fastapi_toolsets/exceptions/handler.py

@@ -1,56 +1,41 @@
 """Exception handlers for FastAPI applications."""
 
+from collections.abc import Callable
 from typing import Any
 
 from fastapi import FastAPI, Request, Response, status
-from fastapi.exceptions import RequestValidationError, ResponseValidationError
-from fastapi.openapi.utils import get_openapi
+from fastapi.exceptions import (
+    HTTPException,
+    RequestValidationError,
+    ResponseValidationError,
+)
 from fastapi.responses import JSONResponse
 
 from ..schemas import ErrorResponse, ResponseStatus
 from .exceptions import ApiException
 
+_VALIDATION_LOCATION_PARAMS: frozenset[str] = frozenset(
+    {"body", "query", "path", "header", "cookie"}
+)
+
 
 def init_exceptions_handlers(app: FastAPI) -> FastAPI:
     """Register exception handlers and custom OpenAPI schema on a FastAPI app.
 
-    Installs handlers for :class:`ApiException`, validation errors, and
-    unhandled exceptions, and replaces the default 422 schema with a
-    consistent error format.
-
     Args:
-        app: FastAPI application instance
+        app: FastAPI application instance.
 
     Returns:
-        The same FastAPI instance (for chaining)
-
-    Example:
-        ```python
-        from fastapi import FastAPI
-        from fastapi_toolsets.exceptions import init_exceptions_handlers
-
-        app = FastAPI()
-        init_exceptions_handlers(app)
-        ```
+        The same FastAPI instance (for chaining).
     """
     _register_exception_handlers(app)
-    app.openapi = lambda: _custom_openapi(app)  # type: ignore[method-assign]
+    _original_openapi = app.openapi
+    app.openapi = lambda: _patched_openapi(app, _original_openapi)  # type: ignore[method-assign]
     return app
 
 
 def _register_exception_handlers(app: FastAPI) -> None:
-    """Register all exception handlers on a FastAPI application.
-
-    Args:
-        app: FastAPI application instance
-
-    Example:
-        from fastapi import FastAPI
-        from fastapi_toolsets.exceptions import init_exceptions_handlers
-
-        app = FastAPI()
-        init_exceptions_handlers(app)
-    """
+    """Register all exception handlers on a FastAPI application."""
 
     @app.exception_handler(ApiException)
     async def api_exception_handler(request: Request, exc: ApiException) -> Response:
@@ -62,12 +47,25 @@ def _register_exception_handlers(app: FastAPI) -> None:
             description=api_error.desc,
             error_code=api_error.err_code,
         )
-
         return JSONResponse(
             status_code=api_error.code,
             content=error_response.model_dump(),
         )
 
+    @app.exception_handler(HTTPException)
+    async def http_exception_handler(request: Request, exc: HTTPException) -> Response:
+        """Handle Starlette/FastAPI HTTPException with a consistent error format."""
+        detail = exc.detail if isinstance(exc.detail, str) else "HTTP Error"
+        error_response = ErrorResponse(
+            message=detail,
+            error_code=f"HTTP-{exc.status_code}",
+        )
+        return JSONResponse(
+            status_code=exc.status_code,
+            content=error_response.model_dump(),
+            headers=getattr(exc, "headers", None),
+        )
+
     @app.exception_handler(RequestValidationError)
     async def request_validation_handler(
         request: Request, exc: RequestValidationError
@@ -90,7 +88,6 @@ def _register_exception_handlers(app: FastAPI) -> None:
             description="An unexpected error occurred. Please try again later.",
             error_code="SERVER-500",
         )
-
         return JSONResponse(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             content=error_response.model_dump(),
@@ -105,11 +102,10 @@ def _format_validation_error(
     formatted_errors = []
 
     for error in errors:
-        field_path = ".".join(
-            str(loc)
-            for loc in error["loc"]
-            if loc not in ("body", "query", "path", "header", "cookie")
-        )
+        locs = error["loc"]
+        if locs and locs[0] in _VALIDATION_LOCATION_PARAMS:
+            locs = locs[1:]
+        field_path = ".".join(str(loc) for loc in locs)
         formatted_errors.append(
             {
                 "field": field_path or "root",
@@ -131,34 +127,22 @@ def _format_validation_error(
     )
 
 
-def _custom_openapi(app: FastAPI) -> dict[str, Any]:
-    """Generate custom OpenAPI schema with standardized error format.
-
-    Replaces default 422 validation error responses with the custom format.
+def _patched_openapi(
+    app: FastAPI, original_openapi: Callable[[], dict[str, Any]]
+) -> dict[str, Any]:
+    """Generate the OpenAPI schema and replace default 422 responses.
 
     Args:
-        app: FastAPI application instance
+        app: FastAPI application instance.
+        original_openapi: The previous ``app.openapi`` callable to delegate to.
 
     Returns:
-        OpenAPI schema dict
-
-    Example:
-        from fastapi import FastAPI
-        from fastapi_toolsets.exceptions import init_exceptions_handlers
-
-        app = FastAPI()
-        init_exceptions_handlers(app)  # Automatically sets custom OpenAPI
+        Patched OpenAPI schema dict.
     """
     if app.openapi_schema:
         return app.openapi_schema
 
-    openapi_schema = get_openapi(
-        title=app.title,
-        version=app.version,
-        openapi_version=app.openapi_version,
-        description=app.description,
-        routes=app.routes,
-    )
+    openapi_schema = original_openapi()
 
     for path_data in openapi_schema.get("paths", {}).values():
         for operation in path_data.values():
@@ -168,20 +152,25 @@ def _custom_openapi(app: FastAPI) -> dict[str, Any]:
                         "description": "Validation Error",
                         "content": {
                             "application/json": {
-                                "example": {
-                                    "data": {
-                                        "errors": [
-                                            {
-                                                "field": "field_name",
-                                                "message": "value is not valid",
-                                                "type": "value_error",
-                                            }
-                                        ]
-                                    },
-                                    "status": ResponseStatus.FAIL.value,
-                                    "message": "Validation Error",
-                                    "description": "1 validation error(s) detected",
-                                    "error_code": "VAL-422",
+                                "examples": {
+                                    "VAL-422": {
+                                        "summary": "Validation Error",
+                                        "value": {
+                                            "data": {
+                                                "errors": [
+                                                    {
+                                                        "field": "field_name",
+                                                        "message": "value is not valid",
+                                                        "type": "value_error",
+                                                    }
+                                                ]
+                                            },
+                                            "status": ResponseStatus.FAIL.value,
+                                            "message": "Validation Error",
+                                            "description": "1 validation error(s) detected",
+                                            "error_code": "VAL-422",
+                                        },
+                                    }
                                 }
                             }
                         },

src/fastapi_toolsets/fixtures/utils.py

@@ -1,24 +1,84 @@
 """Fixture loading utilities for database seeding."""
 
 from collections.abc import Callable, Sequence
-from typing import Any, TypeVar
+from typing import Any
 
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import DeclarativeBase
 
 from ..db import get_transaction
 from ..logger import get_logger
+from ..types import ModelType
 from .enum import LoadStrategy
 from .registry import Context, FixtureRegistry
 
 logger = get_logger()
 
-T = TypeVar("T", bound=DeclarativeBase)
+
+async def _load_ordered(
+    session: AsyncSession,
+    registry: FixtureRegistry,
+    ordered_names: list[str],
+    strategy: LoadStrategy,
+) -> dict[str, list[DeclarativeBase]]:
+    """Load fixtures in order."""
+    results: dict[str, list[DeclarativeBase]] = {}
+
+    for name in ordered_names:
+        fixture = registry.get(name)
+        instances = list(fixture.func())
+
+        if not instances:
+            results[name] = []
+            continue
+
+        model_name = type(instances[0]).__name__
+        loaded: list[DeclarativeBase] = []
+
+        async with get_transaction(session):
+            for instance in instances:
+                if strategy == LoadStrategy.INSERT:
+                    session.add(instance)
+                    loaded.append(instance)
+
+                elif strategy == LoadStrategy.MERGE:
+                    merged = await session.merge(instance)
+                    loaded.append(merged)
+
+                else:  # LoadStrategy.SKIP_EXISTING
+                    pk = _get_primary_key(instance)
+                    if pk is not None:
+                        existing = await session.get(type(instance), pk)
+                        if existing is None:
+                            session.add(instance)
+                            loaded.append(instance)
+                    else:
+                        session.add(instance)
+                        loaded.append(instance)
+
+        results[name] = loaded
+        logger.info(f"Loaded fixture '{name}': {len(loaded)} {model_name}(s)")
+
+    return results
+
+
+def _get_primary_key(instance: DeclarativeBase) -> Any | None:
+    """Get the primary key value of a model instance."""
+    mapper = instance.__class__.__mapper__
+    pk_cols = mapper.primary_key
+
+    if len(pk_cols) == 1:
+        return getattr(instance, pk_cols[0].name, None)
+
+    pk_values = tuple(getattr(instance, col.name, None) for col in pk_cols)
+    if all(v is not None for v in pk_values):
+        return pk_values
+    return None
 
 
 def get_obj_by_attr(
-    fixtures: Callable[[], Sequence[T]], attr_name: str, value: Any
-) -> T:
+    fixtures: Callable[[], Sequence[ModelType]], attr_name: str, value: Any
+) -> ModelType:
     """Get a SQLAlchemy model instance by matching an attribute value.
 
     Args:
@@ -57,13 +117,6 @@ async def load_fixtures(
 
     Returns:
         Dict mapping fixture names to loaded instances
-
-    Example:
-        ```python
-        # Loads 'roles' first (dependency), then 'users'
-        result = await load_fixtures(session, fixtures, "users")
-        print(result["users"])  # [User(...), ...]
-        ```
     """
     ordered = registry.resolve_dependencies(*names)
     return await _load_ordered(session, registry, ordered, strategy)
@@ -85,76 +138,6 @@ async def load_fixtures_by_context(
 
     Returns:
         Dict mapping fixture names to loaded instances
-
-    Example:
-        ```python
-        # Load base + testing fixtures
-        await load_fixtures_by_context(
-            session, fixtures,
-            Context.BASE, Context.TESTING
-        )
-        ```
     """
     ordered = registry.resolve_context_dependencies(*contexts)
     return await _load_ordered(session, registry, ordered, strategy)
-
-
-async def _load_ordered(
-    session: AsyncSession,
-    registry: FixtureRegistry,
-    ordered_names: list[str],
-    strategy: LoadStrategy,
-) -> dict[str, list[DeclarativeBase]]:
-    """Load fixtures in order."""
-    results: dict[str, list[DeclarativeBase]] = {}
-
-    for name in ordered_names:
-        fixture = registry.get(name)
-        instances = list(fixture.func())
-
-        if not instances:
-            results[name] = []
-            continue
-
-        model_name = type(instances[0]).__name__
-        loaded: list[DeclarativeBase] = []
-
-        async with get_transaction(session):
-            for instance in instances:
-                if strategy == LoadStrategy.INSERT:
-                    session.add(instance)
-                    loaded.append(instance)
-
-                elif strategy == LoadStrategy.MERGE:
-                    merged = await session.merge(instance)
-                    loaded.append(merged)
-
-                elif strategy == LoadStrategy.SKIP_EXISTING:
-                    pk = _get_primary_key(instance)
-                    if pk is not None:
-                        existing = await session.get(type(instance), pk)
-                        if existing is None:
-                            session.add(instance)
-                            loaded.append(instance)
-                    else:
-                        session.add(instance)
-                        loaded.append(instance)
-
-        results[name] = loaded
-        logger.info(f"Loaded fixture '{name}': {len(loaded)} {model_name}(s)")
-
-    return results
-
-
-def _get_primary_key(instance: DeclarativeBase) -> Any | None:
-    """Get the primary key value of a model instance."""
-    mapper = instance.__class__.__mapper__
-    pk_cols = mapper.primary_key
-
-    if len(pk_cols) == 1:
-        return getattr(instance, pk_cols[0].name, None)
-
-    pk_values = tuple(getattr(instance, col.name, None) for col in pk_cols)
-    if all(v is not None for v in pk_values):
-        return pk_values
-    return None

src/fastapi_toolsets/metrics/handler.py

@@ -53,17 +53,23 @@ def init_metrics(
         logger.debug("Initialising metric provider '%s'", provider.name)
         provider.func()
 
-    collectors = registry.get_collectors()
+    # Partition collectors and cache env check at startup — both are stable for the app lifetime.
+    async_collectors = [
+        c for c in registry.get_collectors() if asyncio.iscoroutinefunction(c.func)
+    ]
+    sync_collectors = [
+        c for c in registry.get_collectors() if not asyncio.iscoroutinefunction(c.func)
+    ]
+    multiprocess_mode = _is_multiprocess()
 
     @app.get(path, include_in_schema=False)
     async def metrics_endpoint() -> Response:
-        for collector in collectors:
-            if asyncio.iscoroutinefunction(collector.func):
-                await collector.func()
-            else:
-                collector.func()
+        for collector in sync_collectors:
+            collector.func()
+        for collector in async_collectors:
+            await collector.func()
 
-        if _is_multiprocess():
+        if multiprocess_mode:
             prom_registry = CollectorRegistry()
             multiprocess.MultiProcessCollector(prom_registry)
             output = generate_latest(prom_registry)

src/fastapi_toolsets/models.py

@@ -0,0 +1,47 @@
+"""SQLAlchemy model mixins for common column patterns."""
+
+import uuid
+from datetime import datetime
+
+from sqlalchemy import DateTime, Uuid, func, text
+from sqlalchemy.orm import Mapped, mapped_column
+
+__all__ = [
+    "UUIDMixin",
+    "CreatedAtMixin",
+    "UpdatedAtMixin",
+    "TimestampMixin",
+]
+
+
+class UUIDMixin:
+    """Mixin that adds a UUID primary key auto-generated by the database."""
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        Uuid,
+        primary_key=True,
+        server_default=text("gen_random_uuid()"),
+    )
+
+
+class CreatedAtMixin:
+    """Mixin that adds a ``created_at`` timestamp column."""
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+    )
+
+
+class UpdatedAtMixin:
+    """Mixin that adds an ``updated_at`` timestamp column."""
+
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+    )
+
+
+class TimestampMixin(CreatedAtMixin, UpdatedAtMixin):
+    """Mixin that combines ``created_at`` and ``updated_at`` timestamp columns."""

src/fastapi_toolsets/schemas.py

@@ -1,10 +1,12 @@
 """Base Pydantic schemas for API responses."""
 
 from enum import Enum
-from typing import Any, ClassVar, Generic, TypeVar
+from typing import Any, ClassVar, Generic
 
 from pydantic import BaseModel, ConfigDict
 
+from .types import DataT
+
 __all__ = [
     "ApiError",
     "CursorPagination",
@@ -16,8 +18,6 @@ __all__ = [
     "ResponseStatus",
 ]
 
-DataT = TypeVar("DataT")
-
 
 class PydanticBase(BaseModel):
     """Base class for all Pydantic models with common configuration."""

src/fastapi_toolsets/types.py

@@ -0,0 +1,27 @@
+"""Shared type aliases for the fastapi-toolsets package."""
+
+from collections.abc import AsyncGenerator, Callable, Mapping
+from typing import Any, TypeVar
+
+from pydantic import BaseModel
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import DeclarativeBase, QueryableAttribute
+from sqlalchemy.orm.attributes import InstrumentedAttribute
+from sqlalchemy.sql.elements import ColumnElement
+
+# Generic TypeVars
+DataT = TypeVar("DataT")
+ModelType = TypeVar("ModelType", bound=DeclarativeBase)
+SchemaType = TypeVar("SchemaType", bound=BaseModel)
+
+# CRUD type aliases
+JoinType = list[tuple[type[DeclarativeBase], Any]]
+M2MFieldType = Mapping[str, QueryableAttribute[Any]]
+OrderByClause = ColumnElement[Any] | QueryableAttribute[Any]
+
+# Search / facet type aliases
+SearchFieldType = InstrumentedAttribute[Any] | tuple[InstrumentedAttribute[Any], ...]
+FacetFieldType = SearchFieldType
+
+# Dependency type aliases
+SessionDependency = Callable[[], AsyncGenerator[AsyncSession, None]]

tests/conftest.py

@@ -92,6 +92,15 @@ class IntRole(Base):
     name: Mapped[str] = mapped_column(String(50), unique=True)
 
 
+class Permission(Base):
+    """Test model with composite primary key."""
+
+    __tablename__ = "permissions"
+
+    subject: Mapped[str] = mapped_column(String(50), primary_key=True)
+    action: Mapped[str] = mapped_column(String(50), primary_key=True)
+
+
 class Event(Base):
     """Test model with DateTime and Date cursor columns."""
 

tests/test_crud_search.py

@@ -1,9 +1,11 @@
 """Tests for CRUD search functionality."""
 
+import inspect
 import uuid
 
 import pytest
 from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.sql.elements import ColumnElement, UnaryExpression
 
 from fastapi_toolsets.crud import (
     CrudFactory,
@@ -11,6 +13,7 @@ from fastapi_toolsets.crud import (
     SearchConfig,
     get_searchable_fields,
 )
+from fastapi_toolsets.exceptions import InvalidOrderFieldError
 from fastapi_toolsets.schemas import OffsetPagination
 
 from .conftest import (
@@ -427,7 +430,7 @@ class TestNoSearchableFieldsError:
         from fastapi_toolsets.exceptions import NoSearchableFieldsError
 
         error = NoSearchableFieldsError(User)
-        assert "User" in str(error)
+        assert "User" in error.api_error.desc
         assert error.model is User
 
     def test_error_raised_when_no_fields(self):
@@ -451,7 +454,7 @@ class TestNoSearchableFieldsError:
             build_search_filters(NoStringModel, "test")
 
         assert exc_info.value.model is NoStringModel
-        assert "NoStringModel" in str(exc_info.value)
+        assert "NoStringModel" in exc_info.value.api_error.desc
 
 
 class TestGetSearchableFields:
@@ -1046,3 +1049,144 @@ class TestFilterParamsSchema:
 
         assert isinstance(result.pagination, OffsetPagination)
         assert result.pagination.total_count == 2
+
+
+class TestOrderParamsSchema:
+    """Tests for AsyncCrud.order_params()."""
+
+    def test_generates_order_by_and_order_params(self):
+        """Returned dependency has order_by and order query params."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username, User.email])
+        dep = UserOrderCrud.order_params()
+
+        param_names = set(inspect.signature(dep).parameters)
+        assert param_names == {"order_by", "order"}
+
+    def test_dependency_name_includes_model_name(self):
+        """Dependency function is named after the model."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params()
+        assert getattr(dep, "__name__") == "UserOrderParams"
+
+    def test_raises_when_no_order_fields(self):
+        """ValueError raised when no order_fields are configured or provided."""
+        with pytest.raises(ValueError, match="no order_fields"):
+            UserCrud.order_params()
+
+    def test_order_fields_override(self):
+        """order_fields= parameter overrides the class-level default."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username, User.email])
+        dep = UserOrderCrud.order_params(order_fields=[User.email])
+
+        param_names = set(inspect.signature(dep).parameters)
+        assert "order_by" in param_names
+        # description should only mention email, not username
+        sig = inspect.signature(dep)
+        description = sig.parameters["order_by"].default.description
+        assert "email" in description
+        assert "username" not in description
+
+    def test_order_by_description_lists_valid_fields(self):
+        """order_by query param description mentions each allowed field."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username, User.email])
+        dep = UserOrderCrud.order_params()
+
+        sig = inspect.signature(dep)
+        description = sig.parameters["order_by"].default.description
+        assert "username" in description
+        assert "email" in description
+
+    def test_default_order_reflected_in_order_default(self):
+        """default_order is used as the default value for order."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep_asc = UserOrderCrud.order_params(default_order="asc")
+        dep_desc = UserOrderCrud.order_params(default_order="desc")
+
+        sig_asc = inspect.signature(dep_asc)
+        sig_desc = inspect.signature(dep_desc)
+        assert sig_asc.parameters["order"].default.default == "asc"
+        assert sig_desc.parameters["order"].default.default == "desc"
+
+    @pytest.mark.anyio
+    async def test_no_order_by_no_default_returns_none(self):
+        """Returns None when order_by is absent and no default_field is set."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params()
+        result = await dep(order_by=None, order="asc")
+        assert result is None
+
+    @pytest.mark.anyio
+    async def test_no_order_by_with_default_field_returns_asc_expression(self):
+        """Returns default_field.asc() when order_by absent and order=asc."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params(default_field=User.username)
+        result = await dep(order_by=None, order="asc")
+        assert isinstance(result, UnaryExpression)
+        assert "ASC" in str(result)
+
+    @pytest.mark.anyio
+    async def test_no_order_by_with_default_field_returns_desc_expression(self):
+        """Returns default_field.desc() when order_by absent and order=desc."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params(default_field=User.username)
+        result = await dep(order_by=None, order="desc")
+        assert isinstance(result, UnaryExpression)
+        assert "DESC" in str(result)
+
+    @pytest.mark.anyio
+    async def test_valid_order_by_asc(self):
+        """Returns field.asc() for a valid order_by with order=asc."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params()
+        result = await dep(order_by="username", order="asc")
+        assert isinstance(result, UnaryExpression)
+        assert "ASC" in str(result)
+
+    @pytest.mark.anyio
+    async def test_valid_order_by_desc(self):
+        """Returns field.desc() for a valid order_by with order=desc."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params()
+        result = await dep(order_by="username", order="desc")
+        assert isinstance(result, UnaryExpression)
+        assert "DESC" in str(result)
+
+    @pytest.mark.anyio
+    async def test_invalid_order_by_raises_invalid_order_field_error(self):
+        """Raises InvalidOrderFieldError for an unknown order_by value."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        dep = UserOrderCrud.order_params()
+        with pytest.raises(InvalidOrderFieldError) as exc_info:
+            await dep(order_by="nonexistent", order="asc")
+        assert exc_info.value.field == "nonexistent"
+        assert "username" in exc_info.value.valid_fields
+
+    @pytest.mark.anyio
+    async def test_multiple_fields_all_resolve(self):
+        """All configured fields resolve correctly via order_by."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username, User.email])
+        dep = UserOrderCrud.order_params()
+        result_username = await dep(order_by="username", order="asc")
+        result_email = await dep(order_by="email", order="desc")
+        assert isinstance(result_username, ColumnElement)
+        assert isinstance(result_email, ColumnElement)
+
+    @pytest.mark.anyio
+    async def test_order_params_integrates_with_get_multi(
+        self, db_session: AsyncSession
+    ):
+        """order_params output is accepted by get_multi(order_by=...)."""
+        UserOrderCrud = CrudFactory(User, order_fields=[User.username])
+        await UserCrud.create(
+            db_session, UserCreate(username="charlie", email="c@test.com")
+        )
+        await UserCrud.create(
+            db_session, UserCreate(username="alice", email="a@test.com")
+        )
+
+        dep = UserOrderCrud.order_params()
+        order_by = await dep(order_by="username", order="asc")
+        results = await UserOrderCrud.get_multi(db_session, order_by=order_by)
+
+        assert results[0].username == "alice"
+        assert results[1].username == "charlie"

tests/test_db.py

@@ -14,6 +14,7 @@ from fastapi_toolsets.db import (
     lock_tables,
     wait_for_row_change,
 )
+from fastapi_toolsets.exceptions import NotFoundError
 
 from .conftest import DATABASE_URL, Base, Role, RoleCrud, User
 
@@ -307,9 +308,9 @@ class TestWaitForRowChange:
 
     @pytest.mark.anyio
     async def test_nonexistent_row_raises(self, db_session: AsyncSession):
-        """Raises LookupError when the row does not exist."""
+        """Raises NotFoundError when the row does not exist."""
         fake_id = uuid.uuid4()
-        with pytest.raises(LookupError, match="not found"):
+        with pytest.raises(NotFoundError, match="not found"):
             await wait_for_row_change(db_session, Role, fake_id, interval=0.05)
 
     @pytest.mark.anyio
@@ -326,7 +327,7 @@ class TestWaitForRowChange:
 
     @pytest.mark.anyio
     async def test_deleted_row_raises(self, db_session: AsyncSession, engine):
-        """Raises LookupError when the row is deleted during polling."""
+        """Raises NotFoundError when the row is deleted during polling."""
         role = Role(name="delete_role")
         db_session.add(role)
         await db_session.commit()
@@ -340,6 +341,6 @@ class TestWaitForRowChange:
                 await other.commit()
 
         delete_task = asyncio.create_task(delete_later())
-        with pytest.raises(LookupError):
+        with pytest.raises(NotFoundError):
             await wait_for_row_change(db_session, Role, role.id, interval=0.05)
         await delete_task

tests/test_example_pagination_search.py

@@ -15,12 +15,14 @@ from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_asyn
 from docs_src.examples.pagination_search.db import get_db
 from docs_src.examples.pagination_search.models import Article, Base, Category
 from docs_src.examples.pagination_search.routes import router
+from fastapi_toolsets.exceptions import init_exceptions_handlers
 
 from .conftest import DATABASE_URL
 
 
 def build_app(session: AsyncSession) -> FastAPI:
     app = FastAPI()
+    init_exceptions_handlers(app)
 
     async def override_get_db():
         yield session
@@ -269,3 +271,125 @@ class TestCursorPagination:
         body = resp.json()
         assert len(body["data"]) == 1
         assert body["data"][0]["title"] == "SQLAlchemy async"
+
+
+class TestOffsetSorting:
+    """Tests for order_by / order query parameters on the offset endpoint."""
+
+    @pytest.mark.anyio
+    async def test_default_order_uses_created_at_asc(
+        self, client: AsyncClient, ex_db_session
+    ):
+        """No order_by → default field (created_at) ASC."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/offset")
+
+        assert resp.status_code == 200
+        titles = [a["title"] for a in resp.json()["data"]]
+        assert titles == ["FastAPI tips", "SQLAlchemy async", "Draft notes"]
+
+    @pytest.mark.anyio
+    async def test_order_by_title_asc(self, client: AsyncClient, ex_db_session):
+        """order_by=title&order=asc returns alphabetical order."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/offset?order_by=title&order=asc")
+
+        assert resp.status_code == 200
+        titles = [a["title"] for a in resp.json()["data"]]
+        assert titles == ["Draft notes", "FastAPI tips", "SQLAlchemy async"]
+
+    @pytest.mark.anyio
+    async def test_order_by_title_desc(self, client: AsyncClient, ex_db_session):
+        """order_by=title&order=desc returns reverse alphabetical order."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/offset?order_by=title&order=desc")
+
+        assert resp.status_code == 200
+        titles = [a["title"] for a in resp.json()["data"]]
+        assert titles == ["SQLAlchemy async", "FastAPI tips", "Draft notes"]
+
+    @pytest.mark.anyio
+    async def test_order_by_created_at_desc(self, client: AsyncClient, ex_db_session):
+        """order_by=created_at&order=desc returns newest-first."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/offset?order_by=created_at&order=desc")
+
+        assert resp.status_code == 200
+        titles = [a["title"] for a in resp.json()["data"]]
+        assert titles == ["Draft notes", "SQLAlchemy async", "FastAPI tips"]
+
+    @pytest.mark.anyio
+    async def test_invalid_order_by_returns_422(
+        self, client: AsyncClient, ex_db_session
+    ):
+        """Unknown order_by field returns 422 with SORT-422 error code."""
+        resp = await client.get("/articles/offset?order_by=nonexistent_field")
+
+        assert resp.status_code == 422
+        body = resp.json()
+        assert body["error_code"] == "SORT-422"
+        assert body["status"] == "FAIL"
+
+
+class TestCursorSorting:
+    """Tests for order_by / order query parameters on the cursor endpoint.
+
+    In cursor_paginate the cursor_column is always the primary sort; order_by
+    acts as a secondary tiebreaker. With the seeded articles (all having unique
+    created_at values) the overall ordering is always created_at ASC regardless
+    of the order_by value — only the valid/invalid field check and the response
+    shape are meaningful here.
+    """
+
+    @pytest.mark.anyio
+    async def test_default_order_uses_created_at_asc(
+        self, client: AsyncClient, ex_db_session
+    ):
+        """No order_by → default field (created_at) ASC."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/cursor")
+
+        assert resp.status_code == 200
+        titles = [a["title"] for a in resp.json()["data"]]
+        assert titles == ["FastAPI tips", "SQLAlchemy async", "Draft notes"]
+
+    @pytest.mark.anyio
+    async def test_order_by_title_asc_accepted(
+        self, client: AsyncClient, ex_db_session
+    ):
+        """order_by=title is a valid field — request succeeds and returns all articles."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/cursor?order_by=title&order=asc")
+
+        assert resp.status_code == 200
+        assert len(resp.json()["data"]) == 3
+
+    @pytest.mark.anyio
+    async def test_order_by_title_desc_accepted(
+        self, client: AsyncClient, ex_db_session
+    ):
+        """order_by=title&order=desc is valid — request succeeds and returns all articles."""
+        await seed(ex_db_session)
+
+        resp = await client.get("/articles/cursor?order_by=title&order=desc")
+
+        assert resp.status_code == 200
+        assert len(resp.json()["data"]) == 3
+
+    @pytest.mark.anyio
+    async def test_invalid_order_by_returns_422(
+        self, client: AsyncClient, ex_db_session
+    ):
+        """Unknown order_by field returns 422 with SORT-422 error code."""
+        resp = await client.get("/articles/cursor?order_by=nonexistent_field")
+
+        assert resp.status_code == 422
+        body = resp.json()
+        assert body["error_code"] == "SORT-422"
+        assert body["status"] == "FAIL"

tests/test_exceptions.py

@@ -2,12 +2,14 @@
 
 import pytest
 from fastapi import FastAPI
+from fastapi.exceptions import HTTPException
 from fastapi.testclient import TestClient
 
 from fastapi_toolsets.exceptions import (
     ApiException,
     ConflictError,
     ForbiddenError,
+    InvalidOrderFieldError,
     NotFoundError,
     UnauthorizedError,
     generate_error_responses,
@@ -35,8 +37,8 @@ class TestApiException:
         assert error.api_error.msg == "I'm a teapot"
         assert str(error) == "I'm a teapot"
 
-    def test_custom_detail_message(self):
-        """Custom detail overrides default message."""
+    def test_detail_overrides_msg_and_str(self):
+        """detail sets both str(exc) and api_error.msg; class-level msg is unchanged."""
 
         class CustomError(ApiException):
             api_error = ApiError(
@@ -46,8 +48,172 @@ class TestApiException:
                 err_code="BAD-400",
             )
 
-        error = CustomError("Custom message")
-        assert str(error) == "Custom message"
+        error = CustomError("Widget not found")
+        assert str(error) == "Widget not found"
+        assert error.api_error.msg == "Widget not found"
+        assert CustomError.api_error.msg == "Bad Request"  # class unchanged
+
+    def test_desc_override(self):
+        """desc kwarg overrides api_error.desc on the instance only."""
+
+        class MyError(ApiException):
+            api_error = ApiError(
+                code=400, msg="Error", desc="Default.", err_code="ERR-400"
+            )
+
+        err = MyError(desc="Custom desc.")
+        assert err.api_error.desc == "Custom desc."
+        assert MyError.api_error.desc == "Default."  # class unchanged
+
+    def test_data_override(self):
+        """data kwarg sets api_error.data on the instance only."""
+
+        class MyError(ApiException):
+            api_error = ApiError(
+                code=400, msg="Error", desc="Default.", err_code="ERR-400"
+            )
+
+        err = MyError(data={"key": "value"})
+        assert err.api_error.data == {"key": "value"}
+        assert MyError.api_error.data is None  # class unchanged
+
+    def test_desc_and_data_override(self):
+        """detail, desc and data can all be overridden together."""
+
+        class MyError(ApiException):
+            api_error = ApiError(
+                code=400, msg="Error", desc="Default.", err_code="ERR-400"
+            )
+
+        err = MyError("custom msg", desc="New desc.", data={"x": 1})
+        assert str(err) == "custom msg"
+        assert err.api_error.msg == "custom msg"  # detail also updates msg
+        assert err.api_error.desc == "New desc."
+        assert err.api_error.data == {"x": 1}
+        assert err.api_error.code == 400  # other fields unchanged
+
+    def test_class_api_error_not_mutated_after_instance_override(self):
+        """Raising with desc/data does not mutate the class-level api_error."""
+
+        class MyError(ApiException):
+            api_error = ApiError(
+                code=400, msg="Error", desc="Default.", err_code="ERR-400"
+            )
+
+        MyError(desc="Changed", data={"x": 1})
+        assert MyError.api_error.desc == "Default."
+        assert MyError.api_error.data is None
+
+    def test_subclass_uses_super_with_desc_and_data(self):
+        """Subclasses can delegate detail/desc/data to super().__init__()."""
+
+        class BuildValidationError(ApiException):
+            api_error = ApiError(
+                code=422,
+                msg="Build Validation Error",
+                desc="The build configuration is invalid.",
+                err_code="BUILD-422",
+            )
+
+            def __init__(self, *errors: str) -> None:
+                super().__init__(
+                    f"{len(errors)} validation error(s)",
+                    desc=", ".join(errors),
+                    data={"errors": [{"message": e} for e in errors]},
+                )
+
+        err = BuildValidationError("Field A is required", "Field B is invalid")
+        assert str(err) == "2 validation error(s)"
+        assert err.api_error.msg == "2 validation error(s)"  # detail set msg
+        assert err.api_error.desc == "Field A is required, Field B is invalid"
+        assert err.api_error.data == {
+            "errors": [
+                {"message": "Field A is required"},
+                {"message": "Field B is invalid"},
+            ]
+        }
+        assert err.api_error.code == 422  # other fields unchanged
+
+    def test_detail_desc_data_in_http_response(self):
+        """detail/desc/data overrides all appear correctly in the FastAPI HTTP response."""
+
+        class DynamicError(ApiException):
+            api_error = ApiError(
+                code=400, msg="Error", desc="Default.", err_code="ERR-400"
+            )
+
+            def __init__(self, message: str) -> None:
+                super().__init__(
+                    message,
+                    desc=f"Detail: {message}",
+                    data={"reason": message},
+                )
+
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/error")
+        async def raise_error():
+            raise DynamicError("something went wrong")
+
+        client = TestClient(app)
+        response = client.get("/error")
+
+        assert response.status_code == 400
+        body = response.json()
+        assert body["message"] == "something went wrong"
+        assert body["description"] == "Detail: something went wrong"
+        assert body["data"] == {"reason": "something went wrong"}
+
+
+class TestApiExceptionGuard:
+    """Tests for the __init_subclass__ api_error guard."""
+
+    def test_missing_api_error_raises_type_error(self):
+        """Defining a subclass without api_error raises TypeError at class creation time."""
+        with pytest.raises(
+            TypeError, match="must define an 'api_error' class attribute"
+        ):
+
+            class BrokenError(ApiException):
+                pass
+
+    def test_abstract_subclass_skips_guard(self):
+        """abstract=True allows intermediate base classes without api_error."""
+
+        class BaseGroupError(ApiException, abstract=True):
+            pass
+
+        # Concrete child must still define it
+        class ConcreteError(BaseGroupError):
+            api_error = ApiError(
+                code=400, msg="Error", desc="Desc.", err_code="ERR-400"
+            )
+
+        err = ConcreteError()
+        assert err.api_error.code == 400
+
+    def test_abstract_child_still_requires_api_error_on_concrete(self):
+        """Concrete subclass of an abstract class must define api_error."""
+
+        class Base(ApiException, abstract=True):
+            pass
+
+        with pytest.raises(
+            TypeError, match="must define an 'api_error' class attribute"
+        ):
+
+            class Concrete(Base):
+                pass
+
+    def test_inherited_api_error_satisfies_guard(self):
+        """Subclass that inherits api_error from a parent does not need its own."""
+
+        class ConcreteError(NotFoundError):
+            pass
+
+        err = ConcreteError()
+        assert err.api_error.code == 404
 
 
 class TestBuiltInExceptions:
@@ -89,7 +255,7 @@ class TestGenerateErrorResponses:
         assert responses[404]["description"] == "Not Found"
 
     def test_generates_multiple_responses(self):
-        """Generates responses for multiple exceptions."""
+        """Generates responses for multiple exceptions with distinct status codes."""
         responses = generate_error_responses(
             UnauthorizedError,
             ForbiddenError,
@@ -100,15 +266,24 @@ class TestGenerateErrorResponses:
         assert 403 in responses
         assert 404 in responses
 
-    def test_response_has_example(self):
-        """Generated response includes example."""
+    def test_response_has_named_example(self):
+        """Generated response uses named examples keyed by err_code."""
         responses = generate_error_responses(NotFoundError)
-        example = responses[404]["content"]["application/json"]["example"]
+        examples = responses[404]["content"]["application/json"]["examples"]
 
-        assert example["status"] == "FAIL"
-        assert example["error_code"] == "RES-404"
-        assert example["message"] == "Not Found"
-        assert example["data"] is None
+        assert "RES-404" in examples
+        value = examples["RES-404"]["value"]
+        assert value["status"] == "FAIL"
+        assert value["error_code"] == "RES-404"
+        assert value["message"] == "Not Found"
+        assert value["data"] is None
+
+    def test_response_example_has_summary(self):
+        """Each named example carries a summary equal to api_error.msg."""
+        responses = generate_error_responses(NotFoundError)
+        example = responses[404]["content"]["application/json"]["examples"]["RES-404"]
+
+        assert example["summary"] == "Not Found"
 
     def test_response_example_with_data(self):
         """Generated response includes data when set on ApiError."""
@@ -123,9 +298,49 @@ class TestGenerateErrorResponses:
             )
 
         responses = generate_error_responses(ErrorWithData)
-        example = responses[400]["content"]["application/json"]["example"]
+        value = responses[400]["content"]["application/json"]["examples"]["BAD-400"][
+            "value"
+        ]
 
-        assert example["data"] == {"details": "some context"}
+        assert value["data"] == {"details": "some context"}
+
+    def test_two_errors_same_code_both_present(self):
+        """Two exceptions with the same HTTP code produce two named examples."""
+
+        class BadRequestA(ApiException):
+            api_error = ApiError(
+                code=400, msg="Bad A", desc="Reason A.", err_code="ERR-A"
+            )
+
+        class BadRequestB(ApiException):
+            api_error = ApiError(
+                code=400, msg="Bad B", desc="Reason B.", err_code="ERR-B"
+            )
+
+        responses = generate_error_responses(BadRequestA, BadRequestB)
+
+        assert 400 in responses
+        examples = responses[400]["content"]["application/json"]["examples"]
+        assert "ERR-A" in examples
+        assert "ERR-B" in examples
+        assert examples["ERR-A"]["value"]["message"] == "Bad A"
+        assert examples["ERR-B"]["value"]["message"] == "Bad B"
+
+    def test_two_errors_same_code_single_top_level_entry(self):
+        """Two exceptions with the same HTTP code produce exactly one top-level entry."""
+
+        class BadRequestA(ApiException):
+            api_error = ApiError(
+                code=400, msg="Bad A", desc="Reason A.", err_code="ERR-A"
+            )
+
+        class BadRequestB(ApiException):
+            api_error = ApiError(
+                code=400, msg="Bad B", desc="Reason B.", err_code="ERR-B"
+            )
+
+        responses = generate_error_responses(BadRequestA, BadRequestB)
+        assert len([k for k in responses if k == 400]) == 1
 
 
 class TestInitExceptionsHandlers:
@@ -249,13 +464,68 @@ class TestInitExceptionsHandlers:
         assert data["status"] == "FAIL"
         assert data["error_code"] == "SERVER-500"
 
-    def test_custom_openapi_schema(self):
-        """Customizes OpenAPI schema for 422 responses."""
+    def test_handles_http_exception(self):
+        """Handles starlette HTTPException with consistent ErrorResponse envelope."""
         app = FastAPI()
         init_exceptions_handlers(app)
 
+        @app.get("/protected")
+        async def protected():
+            raise HTTPException(status_code=403, detail="Forbidden")
+
+        client = TestClient(app)
+        response = client.get("/protected")
+
+        assert response.status_code == 403
+        data = response.json()
+        assert data["status"] == "FAIL"
+        assert data["error_code"] == "HTTP-403"
+        assert data["message"] == "Forbidden"
+
+    def test_handles_http_exception_404_from_route(self):
+        """HTTPException(404) raised inside a route uses the consistent ErrorResponse envelope."""
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/items/{item_id}")
+        async def get_item(item_id: int):
+            raise HTTPException(status_code=404, detail="Item not found")
+
+        client = TestClient(app)
+        response = client.get("/items/99")
+
+        assert response.status_code == 404
+        data = response.json()
+        assert data["status"] == "FAIL"
+        assert data["error_code"] == "HTTP-404"
+        assert data["message"] == "Item not found"
+
+    def test_handles_http_exception_forwards_headers(self):
+        """HTTPException with WWW-Authenticate header forwards it in the response."""
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/secure")
+        async def secure():
+            raise HTTPException(
+                status_code=401,
+                detail="Not authenticated",
+                headers={"WWW-Authenticate": "Bearer"},
+            )
+
+        client = TestClient(app)
+        response = client.get("/secure")
+
+        assert response.status_code == 401
+        assert response.headers.get("www-authenticate") == "Bearer"
+
+    def test_custom_openapi_schema(self):
+        """Customises OpenAPI schema for 422 responses using named examples."""
         from pydantic import BaseModel
 
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
         class Item(BaseModel):
             name: str
 
@@ -268,8 +538,128 @@ class TestInitExceptionsHandlers:
         post_op = openapi["paths"]["/items"]["post"]
         assert "422" in post_op["responses"]
         resp_422 = post_op["responses"]["422"]
-        example = resp_422["content"]["application/json"]["example"]
-        assert example["error_code"] == "VAL-422"
+        examples = resp_422["content"]["application/json"]["examples"]
+        assert "VAL-422" in examples
+        assert examples["VAL-422"]["value"]["error_code"] == "VAL-422"
+
+    def test_custom_openapi_preserves_app_metadata(self):
+        """_patched_openapi preserves custom FastAPI app-level metadata."""
+        app = FastAPI(
+            title="My API",
+            version="2.0.0",
+            description="Custom description",
+        )
+        init_exceptions_handlers(app)
+
+        schema = app.openapi()
+        assert schema["info"]["title"] == "My API"
+        assert schema["info"]["version"] == "2.0.0"
+
+    def test_handles_response_validation_error(self):
+        """Handles ResponseValidationError with a structured 422 response."""
+        from pydantic import BaseModel
+
+        class CountResponse(BaseModel):
+            count: int
+
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/broken", response_model=CountResponse)
+        async def broken():
+            return {"count": "not-a-number"}  # triggers ResponseValidationError
+
+        client = TestClient(app, raise_server_exceptions=False)
+        response = client.get("/broken")
+
+        assert response.status_code == 422
+        data = response.json()
+        assert data["status"] == "FAIL"
+        assert data["error_code"] == "VAL-422"
+        assert "errors" in data["data"]
+
+    def test_handles_validation_error_with_non_standard_loc(self):
+        """Validation error with empty loc tuple maps the field to 'root'."""
+        from fastapi.exceptions import RequestValidationError
+
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/root-error")
+        async def root_error():
+            raise RequestValidationError(
+                [
+                    {
+                        "type": "custom",
+                        "loc": (),
+                        "msg": "root level error",
+                        "input": None,
+                        "url": "",
+                    }
+                ]
+            )
+
+        client = TestClient(app)
+        response = client.get("/root-error")
+
+        assert response.status_code == 422
+        data = response.json()
+        assert data["data"]["errors"][0]["field"] == "root"
+
+    def test_openapi_schema_cached_after_first_call(self):
+        """app.openapi() returns the cached schema on subsequent calls."""
+        from pydantic import BaseModel
+
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        class Item(BaseModel):
+            name: str
+
+        @app.post("/items")
+        async def create_item(item: Item):
+            return item
+
+        schema_first = app.openapi()
+        schema_second = app.openapi()
+        assert schema_first is schema_second
+
+    def test_openapi_skips_operations_without_422(self):
+        """_patched_openapi leaves operations that have no 422 response unchanged."""
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/ping")
+        async def ping():
+            return {"ok": True}
+
+        schema = app.openapi()
+        get_op = schema["paths"]["/ping"]["get"]
+        assert "422" not in get_op["responses"]
+        assert "200" in get_op["responses"]
+
+    def test_openapi_skips_non_dict_path_item_values(self):
+        """_patched_openapi ignores non-dict values in path items (e.g. path-level parameters)."""
+        from fastapi_toolsets.exceptions.handler import _patched_openapi
+
+        app = FastAPI()
+
+        def fake_openapi() -> dict:
+            return {
+                "paths": {
+                    "/items": {
+                        "parameters": [
+                            {"name": "q", "in": "query"}
+                        ],  # list, not a dict
+                        "get": {"responses": {"200": {"description": "OK"}}},
+                    }
+                }
+            }
+
+        schema = _patched_openapi(app, fake_openapi)
+        # The list value was skipped without error; the GET operation is intact
+        assert schema["paths"]["/items"]["parameters"] == [{"name": "q", "in": "query"}]
+        assert "422" not in schema["paths"]["/items"]["get"]["responses"]
 
 
 class TestExceptionIntegration:
@@ -334,3 +724,43 @@ class TestExceptionIntegration:
 
         assert response.status_code == 200
         assert response.json() == {"id": 1}
+
+
+class TestInvalidOrderFieldError:
+    """Tests for InvalidOrderFieldError exception."""
+
+    def test_api_error_attributes(self):
+        """InvalidOrderFieldError has correct api_error metadata."""
+        assert InvalidOrderFieldError.api_error.code == 422
+        assert InvalidOrderFieldError.api_error.err_code == "SORT-422"
+        assert InvalidOrderFieldError.api_error.msg == "Invalid Order Field"
+
+    def test_stores_field_and_valid_fields(self):
+        """InvalidOrderFieldError stores field and valid_fields on the instance."""
+        error = InvalidOrderFieldError("unknown", ["name", "created_at"])
+        assert error.field == "unknown"
+        assert error.valid_fields == ["name", "created_at"]
+
+    def test_description_contains_field_and_valid_fields(self):
+        """api_error.desc mentions the bad field and valid options."""
+        error = InvalidOrderFieldError("bad_field", ["name", "email"])
+        assert "bad_field" in error.api_error.desc
+        assert "name" in error.api_error.desc
+        assert "email" in error.api_error.desc
+
+    def test_handled_as_422_by_exception_handler(self):
+        """init_exceptions_handlers turns InvalidOrderFieldError into a 422 response."""
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/items")
+        async def list_items():
+            raise InvalidOrderFieldError("bad", ["name"])
+
+        client = TestClient(app)
+        response = client.get("/items")
+
+        assert response.status_code == 422
+        data = response.json()
+        assert data["error_code"] == "SORT-422"
+        assert data["status"] == "FAIL"

tests/test_fixtures.py

@@ -14,7 +14,9 @@ from fastapi_toolsets.fixtures import (
     load_fixtures_by_context,
 )
 
-from .conftest import Role, User
+from fastapi_toolsets.fixtures.utils import _get_primary_key
+
+from .conftest import IntRole, Permission, Role, User
 
 
 class TestContext:
@@ -597,6 +599,46 @@ class TestLoadFixtures:
         count = await RoleCrud.count(db_session)
         assert count == 2
 
+    @pytest.mark.anyio
+    async def test_skip_existing_skips_if_record_exists(self, db_session: AsyncSession):
+        """SKIP_EXISTING returns empty loaded list when the record already exists."""
+        registry = FixtureRegistry()
+        role_id = uuid.uuid4()
+
+        @registry.register
+        def roles():
+            return [Role(id=role_id, name="admin")]
+
+        # First load — inserts the record.
+        result1 = await load_fixtures(
+            db_session, registry, "roles", strategy=LoadStrategy.SKIP_EXISTING
+        )
+        assert len(result1["roles"]) == 1
+
+        # Remove from identity map so session.get() queries the DB in the second load.
+        db_session.expunge_all()
+
+        # Second load — record exists in DB, nothing should be added.
+        result2 = await load_fixtures(
+            db_session, registry, "roles", strategy=LoadStrategy.SKIP_EXISTING
+        )
+        assert result2["roles"] == []
+
+    @pytest.mark.anyio
+    async def test_skip_existing_null_pk_inserts(self, db_session: AsyncSession):
+        """SKIP_EXISTING inserts when the instance has no PK set (auto-increment)."""
+        registry = FixtureRegistry()
+
+        @registry.register
+        def int_roles():
+            # No id provided — PK is None before INSERT (autoincrement).
+            return [IntRole(name="member")]
+
+        result = await load_fixtures(
+            db_session, registry, "int_roles", strategy=LoadStrategy.SKIP_EXISTING
+        )
+        assert len(result["int_roles"]) == 1
+
 
 class TestLoadFixturesByContext:
     """Tests for load_fixtures_by_context function."""
@@ -755,3 +797,19 @@ class TestGetObjByAttr:
         """Raises StopIteration when value type doesn't match."""
         with pytest.raises(StopIteration):
             get_obj_by_attr(self.roles, "id", "not-a-uuid")
+
+
+class TestGetPrimaryKey:
+    """Unit tests for the _get_primary_key helper (composite PK paths)."""
+
+    def test_composite_pk_all_set(self):
+        """Returns a tuple when all composite PK values are set."""
+        instance = Permission(subject="post", action="read")
+        pk = _get_primary_key(instance)
+        assert pk == ("post", "read")
+
+    def test_composite_pk_partial_none(self):
+        """Returns None when any composite PK value is None."""
+        instance = Permission(subject="post")  # action is None
+        pk = _get_primary_key(instance)
+        assert pk is None

tests/test_models.py

@@ -0,0 +1,247 @@
+"""Tests for fastapi_toolsets.models mixins."""
+
+import uuid
+
+import pytest
+from sqlalchemy import String
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+from fastapi_toolsets.models import (
+    CreatedAtMixin,
+    TimestampMixin,
+    UUIDMixin,
+    UpdatedAtMixin,
+)
+
+from .conftest import DATABASE_URL
+
+
+class MixinBase(DeclarativeBase):
+    pass
+
+
+class UUIDModel(MixinBase, UUIDMixin):
+    __tablename__ = "mixin_uuid_models"
+
+    name: Mapped[str] = mapped_column(String(50))
+
+
+class UpdatedAtModel(MixinBase, UpdatedAtMixin):
+    __tablename__ = "mixin_updated_at_models"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    name: Mapped[str] = mapped_column(String(50))
+
+
+class CreatedAtModel(MixinBase, CreatedAtMixin):
+    __tablename__ = "mixin_created_at_models"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    name: Mapped[str] = mapped_column(String(50))
+
+
+class TimestampModel(MixinBase, TimestampMixin):
+    __tablename__ = "mixin_timestamp_models"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    name: Mapped[str] = mapped_column(String(50))
+
+
+class FullMixinModel(MixinBase, UUIDMixin, UpdatedAtMixin):
+    __tablename__ = "mixin_full_models"
+
+    name: Mapped[str] = mapped_column(String(50))
+
+
+@pytest.fixture(scope="function")
+async def mixin_session():
+    engine = create_async_engine(DATABASE_URL, echo=False)
+    async with engine.begin() as conn:
+        await conn.run_sync(MixinBase.metadata.create_all)
+
+    session_factory = async_sessionmaker(engine, expire_on_commit=False)
+    session = session_factory()
+
+    try:
+        yield session
+    finally:
+        await session.close()
+        async with engine.begin() as conn:
+            await conn.run_sync(MixinBase.metadata.drop_all)
+        await engine.dispose()
+
+
+class TestUUIDMixin:
+    @pytest.mark.anyio
+    async def test_uuid_generated_by_db(self, mixin_session):
+        """UUID is generated server-side and populated after flush."""
+        obj = UUIDModel(name="test")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+
+        assert obj.id is not None
+        assert isinstance(obj.id, uuid.UUID)
+
+    @pytest.mark.anyio
+    async def test_uuid_is_primary_key(self):
+        """UUIDMixin adds id as primary key column."""
+        pk_cols = [c.name for c in UUIDModel.__table__.primary_key]
+        assert pk_cols == ["id"]
+
+    @pytest.mark.anyio
+    async def test_each_row_gets_unique_uuid(self, mixin_session):
+        """Each inserted row gets a distinct UUID."""
+        a = UUIDModel(name="a")
+        b = UUIDModel(name="b")
+        mixin_session.add_all([a, b])
+        await mixin_session.flush()
+
+        assert a.id != b.id
+
+    @pytest.mark.anyio
+    async def test_uuid_server_default_set(self):
+        """Column has gen_random_uuid() as server default."""
+        col = UUIDModel.__table__.c["id"]
+        assert col.server_default is not None
+        assert "gen_random_uuid" in str(col.server_default.arg)
+
+
+class TestUpdatedAtMixin:
+    @pytest.mark.anyio
+    async def test_updated_at_set_on_insert(self, mixin_session):
+        """updated_at is populated after insert."""
+        obj = UpdatedAtModel(name="initial")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert obj.updated_at is not None
+        assert obj.updated_at.tzinfo is not None  # timezone-aware
+
+    @pytest.mark.anyio
+    async def test_updated_at_changes_on_update(self, mixin_session):
+        """updated_at is updated when the row is modified."""
+        obj = UpdatedAtModel(name="initial")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        original_ts = obj.updated_at
+
+        obj.name = "modified"
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert obj.updated_at >= original_ts
+
+    @pytest.mark.anyio
+    async def test_updated_at_column_is_not_nullable(self):
+        """updated_at column is non-nullable."""
+        col = UpdatedAtModel.__table__.c["updated_at"]
+        assert not col.nullable
+
+    @pytest.mark.anyio
+    async def test_updated_at_has_server_default(self):
+        """updated_at column has a server-side default."""
+        col = UpdatedAtModel.__table__.c["updated_at"]
+        assert col.server_default is not None
+
+    @pytest.mark.anyio
+    async def test_updated_at_has_onupdate(self):
+        """updated_at column has an onupdate clause."""
+        col = UpdatedAtModel.__table__.c["updated_at"]
+        assert col.onupdate is not None
+
+
+class TestCreatedAtMixin:
+    @pytest.mark.anyio
+    async def test_created_at_set_on_insert(self, mixin_session):
+        """created_at is populated after insert."""
+        obj = CreatedAtModel(name="new")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert obj.created_at is not None
+        assert obj.created_at.tzinfo is not None  # timezone-aware
+
+    @pytest.mark.anyio
+    async def test_created_at_not_changed_on_update(self, mixin_session):
+        """created_at is not modified when the row is updated."""
+        obj = CreatedAtModel(name="original")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        original_ts = obj.created_at
+
+        obj.name = "updated"
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert obj.created_at == original_ts
+
+    @pytest.mark.anyio
+    async def test_created_at_column_is_not_nullable(self):
+        """created_at column is non-nullable."""
+        col = CreatedAtModel.__table__.c["created_at"]
+        assert not col.nullable
+
+    @pytest.mark.anyio
+    async def test_created_at_has_no_onupdate(self):
+        """created_at column has no onupdate clause."""
+        col = CreatedAtModel.__table__.c["created_at"]
+        assert col.onupdate is None
+
+
+class TestTimestampMixin:
+    @pytest.mark.anyio
+    async def test_both_columns_set_on_insert(self, mixin_session):
+        """created_at and updated_at are both populated after insert."""
+        obj = TimestampModel(name="new")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert obj.created_at is not None
+        assert obj.updated_at is not None
+
+    @pytest.mark.anyio
+    async def test_created_at_stable_updated_at_changes_on_update(self, mixin_session):
+        """On update: created_at stays the same, updated_at advances."""
+        obj = TimestampModel(name="original")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        original_created = obj.created_at
+        original_updated = obj.updated_at
+
+        obj.name = "modified"
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert obj.created_at == original_created
+        assert obj.updated_at >= original_updated
+
+    @pytest.mark.anyio
+    async def test_timestamp_mixin_has_both_columns(self):
+        """TimestampModel exposes both created_at and updated_at columns."""
+        col_names = {c.name for c in TimestampModel.__table__.columns}
+        assert "created_at" in col_names
+        assert "updated_at" in col_names
+
+
+class TestFullMixinModel:
+    @pytest.mark.anyio
+    async def test_combined_mixins_work_together(self, mixin_session):
+        """UUIDMixin and UpdatedAtMixin can be combined on the same model."""
+        obj = FullMixinModel(name="combined")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+        await mixin_session.refresh(obj)
+
+        assert isinstance(obj.id, uuid.UUID)
+        assert obj.updated_at is not None
+        assert obj.updated_at.tzinfo is not None

uv.lock

@@ -251,7 +251,7 @@ wheels = [
 
 [[package]]
 name = "fastapi-toolsets"
-version = "1.2.1"
+version = "2.0.0"
 source = { editable = "." }
 dependencies = [
     { name = "asyncpg" },

zensical.toml

@@ -77,6 +77,10 @@ md_in_html = {}
 "pymdownx.tasklist" = {custom_checkbox = true}
 "pymdownx.tilde" = {}
 
+[project.markdown_extensions.pymdownx.emoji]
+emoji_index = "zensical.extensions.emoji.twemoji"
+emoji_generator = "zensical.extensions.emoji.to_svg"
+
 [project.markdown_extensions."pymdownx.highlight"]
 anchor_linenums = true
 line_spans = "__span"
@@ -95,3 +99,49 @@ permalink = true
 [project.markdown_extensions."pymdownx.snippets"]
 base_path = ["."]
 check_paths = true
+
+[[project.nav]]
+Home = "index.md"
+
+[[project.nav]]
+Modules = [
+    {CLI = "module/cli.md"},
+    {CRUD = "module/crud.md"},
+    {Database = "module/db.md"},
+    {Dependencies = "module/dependencies.md"},
+    {Exceptions = "module/exceptions.md"},
+    {Fixtures = "module/fixtures.md"},
+    {Logger = "module/logger.md"},
+    {Metrics = "module/metrics.md"},
+    {Models = "module/models.md"},
+    {Pytest = "module/pytest.md"},
+    {Schemas = "module/schemas.md"},
+]
+
+[[project.nav]]
+Reference = [
+    {CLI = "reference/cli.md"},
+    {CRUD = "reference/crud.md"},
+    {Database = "reference/db.md"},
+    {Dependencies = "reference/dependencies.md"},
+    {Exceptions = "reference/exceptions.md"},
+    {Fixtures = "reference/fixtures.md"},
+    {Logger = "reference/logger.md"},
+    {Metrics = "reference/metrics.md"},
+    {Models = "reference/models.md"},
+    {Pytest = "reference/pytest.md"},
+    {Schemas = "reference/schemas.md"},
+]
+
+[[project.nav]]
+Examples = [
+    {"Pagination & Search" = "examples/pagination-search.md"},
+]
+
+[[project.nav]]
+Migration = [
+    {"v2.0" = "migration/v2.md"},
+]
+
+[[project.nav]]
+"Changelog ↗" = "https://github.com/d3vyce/fastapi-toolsets/releases"