diff --git a/docs/module/security.md b/docs/module/security.md
new file mode 100644
index 0000000..6ddddb5
--- /dev/null
+++ b/docs/module/security.md
@@ -0,0 +1,267 @@
+# Security
+
+Composable authentication helpers for FastAPI that use `Security()` for OpenAPI documentation and accept user-provided validator functions with full type flexibility.
+
+## Overview
+
+The `security` module provides four auth source classes and a `MultiAuth` factory. Each class wraps a FastAPI security scheme for OpenAPI and accepts a validator function called as:
+
+```python
+await validator(credential, **kwargs)
+```
+
+where `kwargs` are the extra keyword arguments provided at instantiation (roles, permissions, enums, etc.). The validator returns the authenticated identity (e.g. a `User` model) which becomes the route dependency value.
+
+```python
+from fastapi import Security
+from fastapi_toolsets.security import BearerTokenAuth
+
+async def verify_token(token: str, *, role: str) -> User:
+    user = await db.get_by_token(token)
+    if not user or user.role != role:
+        raise UnauthorizedError()
+    return user
+
+bearer_admin = BearerTokenAuth(verify_token, role="admin")
+
+@app.get("/admin")
+async def admin_route(user: User = Security(bearer_admin)):
+    return user
+```
+
+## Auth sources
+
+### [`BearerTokenAuth`](../reference/security.md#fastapi_toolsets.security.BearerTokenAuth)
+
+Reads the `Authorization: Bearer <token>` header. Wraps `HTTPBearer` for OpenAPI.
+
+```python
+from fastapi_toolsets.security import BearerTokenAuth
+
+bearer = BearerTokenAuth(validator=verify_token)
+
+@app.get("/me")
+async def me(user: User = Security(bearer)):
+    return user
+```
+
+#### Token prefix
+
+The optional `prefix` parameter restricts a `BearerTokenAuth` instance to tokens
+that start with a given string. The prefix is **kept** in the value passed to the
+validator — store and compare tokens with their prefix included.
+
+This lets you deploy multiple `BearerTokenAuth` instances in the same application
+and disambiguate them efficiently in `MultiAuth`:
+
+```python
+user_bearer = BearerTokenAuth(verify_user, prefix="user_")  # matches "Bearer user_..."
+org_bearer  = BearerTokenAuth(verify_org,  prefix="org_")   # matches "Bearer org_..."
+```
+
+Use [`generate_token()`](#token-generation) to create correctly-prefixed tokens.
+
+#### Token generation
+
+`BearerTokenAuth.generate_token()` produces a secure random token ready to store
+in your database and return to the client. If a prefix is configured it is
+prepended automatically:
+
+```python
+bearer = BearerTokenAuth(verify_token, prefix="user_")
+
+token = bearer.generate_token()   # e.g. "user_Xk3mN..."
+await db.store_token(user_id, token)
+return {"access_token": token, "token_type": "bearer"}
+```
+
+The client sends `Authorization: Bearer user_Xk3mN...` and the validator receives
+the full token (prefix included) to compare against the stored value.
+
+### [`CookieAuth`](../reference/security.md#fastapi_toolsets.security.CookieAuth)
+
+Reads a named cookie. Wraps `APIKeyCookie` for OpenAPI.
+
+```python
+from fastapi_toolsets.security import CookieAuth
+
+cookie_auth = CookieAuth("session", validator=verify_session)
+
+@app.get("/me")
+async def me(user: User = Security(cookie_auth)):
+    return user
+```
+
+### [`OAuth2Auth`](../reference/security.md#fastapi_toolsets.security.OAuth2Auth)
+
+Reads the `Authorization: Bearer <token>` header and registers the token endpoint
+in OpenAPI via `OAuth2PasswordBearer`.
+
+```python
+from fastapi_toolsets.security import OAuth2Auth
+
+oauth2_auth = OAuth2Auth(token_url="/token", validator=verify_token)
+
+@app.get("/me")
+async def me(user: User = Security(oauth2_auth)):
+    return user
+```
+
+### [`OpenIDAuth`](../reference/security.md#fastapi_toolsets.security.OpenIDAuth)
+
+Reads the `Authorization: Bearer <token>` header and registers the OpenID Connect
+discovery URL in OpenAPI via `OpenIdConnect`. Token validation is fully delegated
+to your validator — use any OIDC / JWT library (`authlib`, `python-jose`, `PyJWT`).
+
+```python
+from fastapi_toolsets.security import OpenIDAuth
+
+async def verify_google_token(token: str, *, audience: str) -> User:
+    payload = jwt.decode(token, google_public_keys, algorithms=["RS256"],
+                         audience=audience)
+    return User(email=payload["email"], name=payload["name"])
+
+google_auth = OpenIDAuth(
+    "https://accounts.google.com/.well-known/openid-configuration",
+    verify_google_token,
+    audience="my-client-id",
+)
+
+@app.get("/me")
+async def me(user: User = Security(google_auth)):
+    return user
+```
+
+The discovery URL is used **only for OpenAPI documentation** — no requests are made
+to it by this class. You are responsible for fetching and caching the provider's
+public keys in your validator.
+
+Multiple providers work naturally with `MultiAuth`:
+
+```python
+multi = MultiAuth(google_auth, github_auth)
+
+@app.get("/data")
+async def data(user: User = Security(multi)):
+    return user
+```
+
+## Typed validator kwargs
+
+All auth classes forward extra instantiation keyword arguments to the validator.
+Arguments can be any type — enums, strings, integers, etc. The validator returns
+the authenticated identity, which FastAPI injects directly into the route handler.
+
+```python
+async def verify_token(token: str, *, role: Role, permission: str) -> User:
+    user = await decode_token(token)
+    if user.role != role or permission not in user.permissions:
+        raise UnauthorizedError()
+    return user
+
+bearer = BearerTokenAuth(verify_token, role=Role.ADMIN, permission="billing:read")
+```
+
+Each auth instance is self-contained — create a separate instance per distinct
+requirement instead of passing requirements through `Security(scopes=[...])`.
+
+### Using `.require()` inline
+
+If declaring a new top-level variable per role feels verbose, use `.require()` to
+create a configured clone directly in the route decorator. The original instance
+is not mutated:
+
+```python
+bearer = BearerTokenAuth(verify_token)
+
+@app.get("/admin/stats")
+async def admin_stats(user: User = Security(bearer.require(role=Role.ADMIN))):
+    return {"message": f"Hello admin {user.name}"}
+
+@app.get("/profile")
+async def profile(user: User = Security(bearer.require(role=Role.USER))):
+    return {"id": user.id, "name": user.name}
+```
+
+`.require()` kwargs are merged over existing ones — new values win on conflict.
+The `prefix` (for `BearerTokenAuth`) and cookie name (for `CookieAuth`) are
+always preserved.
+
+`.require()` instances work transparently inside `MultiAuth`:
+
+```python
+multi = MultiAuth(
+    user_bearer.require(role=Role.USER),
+    org_bearer.require(role=Role.ADMIN),
+)
+```
+
+## MultiAuth
+
+[`MultiAuth`](../reference/security.md#fastapi_toolsets.security.MultiAuth) combines
+multiple auth sources into a single callable. Sources are tried in order; the
+first one that finds a credential wins.
+
+```python
+from fastapi_toolsets.security import MultiAuth
+
+multi = MultiAuth(user_bearer, org_bearer, cookie_auth)
+
+@app.get("/data")
+async def data_route(user = Security(multi)):
+    return user
+```
+
+### Using `.require()` on MultiAuth
+
+`MultiAuth` also supports `.require()`, which propagates the kwargs to every
+source that implements it. Sources that do not (e.g. custom `AuthSource`
+subclasses) are passed through unchanged:
+
+```python
+multi = MultiAuth(bearer, cookie)
+
+@app.get("/admin")
+async def admin(user: User = Security(multi.require(role=Role.ADMIN))):
+    return user
+```
+
+This is equivalent to calling `.require()` on each source individually:
+
+```python
+# These two are identical
+multi.require(role=Role.ADMIN)
+
+MultiAuth(
+    bearer.require(role=Role.ADMIN),
+    cookie.require(role=Role.ADMIN),
+)
+```
+
+### Prefix-based dispatch
+
+Because `extract()` is pure string matching (no I/O), prefix-based source
+selection is essentially free. Only the matching source's validator (which may
+involve DB or network I/O) is ever called:
+
+```python
+user_bearer = BearerTokenAuth(verify_user, prefix="user_")
+org_bearer  = BearerTokenAuth(verify_org,  prefix="org_")
+
+multi = MultiAuth(user_bearer, org_bearer)
+
+# "Bearer user_alice" → only verify_user runs, receives "user_alice"
+# "Bearer org_acme"   → only verify_org runs, receives "org_acme"
+```
+
+Tokens are stored and compared **with their prefix** — use `generate_token()` on
+each source to issue correctly-prefixed tokens:
+
+```python
+user_token = user_bearer.generate_token()  # "user_..."
+org_token  = org_bearer.generate_token()   # "org_..."
+```
+
+---
+
+[:material-api: API Reference](../reference/security.md)
diff --git a/docs/reference/security.md b/docs/reference/security.md
new file mode 100644
index 0000000..f38235d
--- /dev/null
+++ b/docs/reference/security.md
@@ -0,0 +1,28 @@
+# `security`
+
+Here's the reference for the authentication helpers provided by the `security` module.
+
+You can import them directly from `fastapi_toolsets.security`:
+
+```python
+from fastapi_toolsets.security import (
+    AuthSource,
+    BearerTokenAuth,
+    CookieAuth,
+    OAuth2Auth,
+    OpenIDAuth,
+    MultiAuth,
+)
+```
+
+## ::: fastapi_toolsets.security.AuthSource
+
+## ::: fastapi_toolsets.security.BearerTokenAuth
+
+## ::: fastapi_toolsets.security.CookieAuth
+
+## ::: fastapi_toolsets.security.OAuth2Auth
+
+## ::: fastapi_toolsets.security.OpenIDAuth
+
+## ::: fastapi_toolsets.security.MultiAuth
diff --git a/src/fastapi_toolsets/security/__init__.py b/src/fastapi_toolsets/security/__init__.py
new file mode 100644
index 0000000..2ff9c43
--- /dev/null
+++ b/src/fastapi_toolsets/security/__init__.py
@@ -0,0 +1,14 @@
+"""Authentication helpers for FastAPI using Security()."""
+
+from .base import AuthSource
+from .multi import MultiAuth
+from .sources import BearerTokenAuth, CookieAuth, OAuth2Auth, OpenIDAuth
+
+__all__ = [
+    "AuthSource",
+    "BearerTokenAuth",
+    "CookieAuth",
+    "OAuth2Auth",
+    "OpenIDAuth",
+    "MultiAuth",
+]
diff --git a/src/fastapi_toolsets/security/base.py b/src/fastapi_toolsets/security/base.py
new file mode 100644
index 0000000..7d82db7
--- /dev/null
+++ b/src/fastapi_toolsets/security/base.py
@@ -0,0 +1,112 @@
+"""Abstract base class for authentication sources."""
+
+import inspect
+from abc import ABC, abstractmethod
+from typing import Any, Callable
+
+from fastapi import Request
+from fastapi.security import SecurityScopes
+
+from fastapi_toolsets.exceptions import UnauthorizedError
+
+
+class AuthSource(ABC):
+    """Abstract base class for authentication sources.
+
+    Subclass this to create a custom auth source that works with
+    :func:`~fastapi_toolsets.security.MultiAuth` and can be used directly
+    with :func:`fastapi.Security`.
+
+    Concrete subclasses must implement :meth:`extract` and
+    :meth:`authenticate`. The default :meth:`__call__` (set up in
+    :meth:`__init__`) wires them together for FastAPI dependency injection.
+
+    Custom subclasses with their own ``__init__`` **must** call
+    ``super().__init__()`` to activate the default dependency behaviour::
+
+        class JWTAuth(AuthSource):
+            def __init__(self, secret: str, *, role: str | None = None):
+                super().__init__()   # required
+                self._secret = secret
+                self._role = role
+
+            async def extract(self, request: Request) -> str | None:
+                auth = request.headers.get("Authorization", "")
+                if not auth.startswith("Bearer "):
+                    return None
+                return auth[7:] or None
+
+            async def authenticate(self, credential: str) -> User:
+                payload = jwt.decode(credential, self._secret)
+                if self._role and payload.get("role") != self._role:
+                    raise UnauthorizedError()
+                return User(**payload)
+
+        jwt_auth = JWTAuth(secret="mysecret")
+
+        @app.get("/me")
+        async def me(user: User = Security(jwt_auth)):
+            return user
+
+        # Works with MultiAuth too
+        multi = MultiAuth(jwt_auth, CookieAuth("session", verify_session))
+
+    .. note::
+        The default ``__call__`` does not register a security scheme in the
+        OpenAPI spec. Built-in sources (``BearerTokenAuth`` etc.) override
+        ``__call__`` using the ``__signature__`` trick to provide a FastAPI
+        security scheme for Swagger UI.
+    """
+
+    def __init__(self) -> None:
+        """Set up the default FastAPI dependency signature.
+
+        Creates a closure that FastAPI can introspect to inject
+        :class:`fastapi.Request` and :class:`fastapi.security.SecurityScopes`.
+        The :meth:`__signature__` attribute is set so that ``inspect.signature``
+        (which FastAPI uses internally) returns the correct parameter list.
+
+        Subclasses with their own ``__init__`` must call ``super().__init__()``.
+        Built-in subclasses (``BearerTokenAuth`` etc.) skip this and set up
+        their own ``_call_fn`` / ``__signature__`` directly.
+        """
+        source = self
+
+        async def _call(
+            request: Request,
+            security_scopes: SecurityScopes,  # noqa: ARG001
+        ) -> Any:
+            credential = await source.extract(request)
+            if credential is None:
+                raise UnauthorizedError()
+            return await source.authenticate(credential)
+
+        self._call_fn: Callable[..., Any] = _call
+        self.__signature__ = inspect.signature(_call)
+
+    @abstractmethod
+    async def extract(self, request: Request) -> str | None:
+        """Extract the raw credential from the request without validating.
+
+        Returns ``None`` if no credential is present for this source.
+        This method must be fast and free of I/O — it is called by
+        :func:`~fastapi_toolsets.security.MultiAuth` for every source on
+        every request.
+        """
+
+    @abstractmethod
+    async def authenticate(self, credential: str) -> Any:
+        """Validate a credential and return the authenticated identity.
+
+        Should raise :class:`~fastapi_toolsets.exceptions.UnauthorizedError`
+        (or any exception) when the credential is invalid. The return value
+        is injected into the route handler as the dependency value.
+        """
+
+    async def __call__(self, **kwargs: Any) -> Any:
+        """FastAPI dependency dispatch.
+
+        Delegates to the closure stored in ``_call_fn``, whose signature
+        (stored in ``__signature__``) tells FastAPI which parameters to inject.
+        """
+        return await self._call_fn(**kwargs)
diff --git a/src/fastapi_toolsets/security/multi.py b/src/fastapi_toolsets/security/multi.py
new file mode 100644
index 0000000..9420f40
--- /dev/null
+++ b/src/fastapi_toolsets/security/multi.py
@@ -0,0 +1,98 @@
+"""MultiAuth: combine multiple authentication sources into a single callable."""
+
+import inspect
+from typing import Any, cast
+
+from fastapi import Request
+from fastapi.security import SecurityScopes
+
+from fastapi_toolsets.exceptions import UnauthorizedError
+
+from .base import AuthSource
+
+
+class MultiAuth:
+    """Combine multiple authentication sources into a single callable.
+
+    Sources are tried in order; the first one whose
+    :meth:`~AuthSource.extract` returns a non-``None`` credential wins.
+    Its :meth:`~AuthSource.authenticate` is called and the result returned.
+
+    If a credential is found but the validator raises, the exception propagates
+    immediately — the remaining sources are **not** tried. This prevents
+    silent fallthrough on invalid credentials.
+
+    If no source provides a credential,
+    :class:`~fastapi_toolsets.exceptions.UnauthorizedError` is raised.
+
+    The :meth:`~AuthSource.extract` method of each source performs only
+    string matching (no I/O), so prefix-based dispatch is essentially free.
+
+    Any :class:`~AuthSource` subclass — including user-defined ones — can be
+    passed as a source.
+
+    Args:
+        *sources: Auth source instances to try in order.
+
+    Example::
+
+        user_bearer = BearerTokenAuth(verify_user, prefix="user_")
+        org_bearer  = BearerTokenAuth(verify_org,  prefix="org_")
+        cookie      = CookieAuth("session", verify_session)
+
+        multi = MultiAuth(user_bearer, org_bearer, cookie)
+
+        @app.get("/data")
+        async def data_route(user = Security(multi)):
+            return user
+
+        # Apply a shared requirement to all sources at once
+        @app.get("/admin")
+        async def admin_route(user = Security(multi.require(role=Role.ADMIN))):
+            return user
+    """
+
+    def __init__(self, *sources: AuthSource) -> None:
+        self._sources = sources
+
+        _sources = sources
+
+        async def _call(
+            request: Request,
+            security_scopes: SecurityScopes,  # noqa: ARG001
+        ) -> Any:
+            for source in _sources:
+                credential = await source.extract(request)
+                if credential is not None:
+                    return await source.authenticate(credential)
+            raise UnauthorizedError()
+
+        self._call_fn = _call
+        self.__signature__ = inspect.signature(_call)
+
+    async def __call__(self, **kwargs: Any) -> Any:
+        return await self._call_fn(**kwargs)
+
+    def require(self, **kwargs: Any) -> "MultiAuth":
+        """Return a new :class:`MultiAuth` with kwargs forwarded to each source.
+
+        Calls ``.require(**kwargs)`` on every source that supports it. Sources
+        that do not implement ``.require()`` (e.g. custom :class:`~AuthSource`
+        subclasses) are passed through unchanged.
+
+        New kwargs are merged over each source's existing kwargs — new values
+        win on conflict::
+
+            multi = MultiAuth(bearer, cookie)
+
+            @app.get("/admin")
+            async def admin(user = Security(multi.require(role=Role.ADMIN))):
+                return user
+        """
+        new_sources = tuple(
+            cast(Any, source).require(**kwargs)
+            if hasattr(source, "require")
+            else source
+            for source in self._sources
+        )
+        return MultiAuth(*new_sources)
diff --git a/src/fastapi_toolsets/security/sources/__init__.py b/src/fastapi_toolsets/security/sources/__init__.py
new file mode 100644
index 0000000..5fd948f
--- /dev/null
+++ b/src/fastapi_toolsets/security/sources/__init__.py
@@ -0,0 +1,8 @@
+"""Built-in authentication source implementations."""
+
+from .bearer import BearerTokenAuth
+from .cookie import CookieAuth
+from .oauth2 import OAuth2Auth
+from .openid import OpenIDAuth
+
+__all__ = ["BearerTokenAuth", "CookieAuth", "OAuth2Auth", "OpenIDAuth"]
diff --git a/src/fastapi_toolsets/security/sources/bearer.py b/src/fastapi_toolsets/security/sources/bearer.py
new file mode 100644
index 0000000..7eefcf7
--- /dev/null
+++ b/src/fastapi_toolsets/security/sources/bearer.py
@@ -0,0 +1,171 @@
+"""Bearer token authentication source."""
+
+import inspect
+import secrets
+from typing import Annotated, Any, Callable
+
+from fastapi import Depends
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer, SecurityScopes
+
+from fastapi_toolsets.exceptions import UnauthorizedError
+
+from ..base import AuthSource
+
+
+class BearerTokenAuth(AuthSource):
+    """Bearer token authentication source.
+
+    Wraps :class:`fastapi.security.HTTPBearer` for OpenAPI documentation.
+    The validator is called as ``await validator(credential, **kwargs)``
+    where ``kwargs`` are the extra keyword arguments provided at instantiation.
+
+    Args:
+        validator: Async callable that receives the credential and any extra
+            keyword arguments, and returns the authenticated identity (e.g. a
+            ``User`` model). Should raise
+            :class:`~fastapi_toolsets.exceptions.UnauthorizedError` on failure.
+        prefix: Optional token prefix (e.g. ``"user_"``). If set, only tokens
+            whose value starts with this prefix are matched. The prefix is
+            **kept** in the value passed to the validator — store and compare
+            tokens with their prefix included. Use :meth:`generate_token` to
+            create correctly-prefixed tokens. This enables multiple
+            ``BearerTokenAuth`` instances in the same app (e.g. ``"user_"``
+            for user tokens, ``"org_"`` for org tokens).
+        **kwargs: Extra keyword arguments forwarded to the validator on every
+            call (e.g. ``role=Role.ADMIN``).
+
+    Example::
+
+        async def verify_token(token: str, *, role: Role) -> User:
+            user = await db.get_by_token(token)   # token includes prefix
+            if not user or user.role != role:
+                raise UnauthorizedError()
+            return user
+
+        bearer_admin = BearerTokenAuth(verify_token, prefix="user_", role=Role.ADMIN)
+
+        # Generate a token to store in DB and return to the client:
+        token = bearer_admin.generate_token()   # e.g. "user_Xk3..."
+
+        @app.get("/admin")
+        async def admin_route(user: User = Security(bearer_admin)):
+            return user
+    """
+
+    def __init__(
+        self,
+        validator: Callable[..., Any],
+        *,
+        prefix: str | None = None,
+        **kwargs: Any,
+    ) -> None:
+        self._validator = validator
+        self._prefix = prefix
+        self._kwargs = kwargs
+        self._scheme = HTTPBearer(auto_error=False)
+
+        # Capture locals for the closure — self._scheme cannot be referenced
+        # inside the Annotated default because annotations are evaluated at
+        # function-definition time (no `from __future__ import annotations`).
+        _scheme = self._scheme
+        _validator = validator
+        _kwargs = kwargs
+        _prefix = prefix
+
+        async def _call(
+            # security_scopes is unused in the body but its presence in the
+            # signature tells FastAPI to aggregate scopes from Security() calls
+            # up the dependency chain and expose them in the OpenAPI schema.
+            security_scopes: SecurityScopes,  # noqa: ARG001
+            credentials: Annotated[
+                HTTPAuthorizationCredentials | None, Depends(_scheme)
+            ] = None,
+        ) -> Any:
+            if credentials is None:
+                raise UnauthorizedError()
+            token = credentials.credentials
+            if _prefix is not None and not token.startswith(_prefix):
+                raise UnauthorizedError()
+            return await _validator(token, **_kwargs)
+
+        # __call__ must be defined on the class (not the instance) so that
+        # callable(self) returns True. We expose the closure's signature via
+        # __signature__ so FastAPI resolves the correct sub-dependencies.
+        self._call_fn = _call
+        self.__signature__ = inspect.signature(_call)
+
+    async def __call__(self, **kwargs: Any) -> Any:
+        return await self._call_fn(**kwargs)
+
+    async def extract(self, request: Any) -> str | None:
+        """Extract the raw credential from the request without validating.
+
+        Returns ``None`` if no ``Authorization: Bearer`` header is present,
+        the token is empty, or the token does not match the configured prefix.
+        The prefix is included in the returned value.
+        """
+        auth = request.headers.get("Authorization", "")
+        if not auth.startswith("Bearer "):
+            return None
+        token = auth[7:]
+        if not token:
+            return None
+        if self._prefix is not None and not token.startswith(self._prefix):
+            return None
+        return token
+
+    async def authenticate(self, credential: str) -> Any:
+        """Validate a credential and return the identity.
+
+        Calls ``await validator(credential, **kwargs)`` where ``kwargs`` are
+        the extra keyword arguments provided at instantiation.
+        """
+        return await self._validator(credential, **self._kwargs)
+
+    def require(self, **kwargs: Any) -> "BearerTokenAuth":
+        """Return a new instance with additional (or overriding) validator kwargs.
+
+        Useful for specifying per-endpoint requirements inline without
+        declaring a new top-level variable::
+
+            bearer = BearerTokenAuth(verify_token)
+
+            @app.get("/admin")
+            async def admin(user: User = Security(bearer.require(role=Role.ADMIN))):
+                return user
+
+        The ``prefix`` is preserved. New kwargs are merged over existing ones
+        (new values win on conflict).
+        """
+        return BearerTokenAuth(
+            self._validator,
+            prefix=self._prefix,
+            **{**self._kwargs, **kwargs},
+        )
+
+    def generate_token(self, nbytes: int = 32) -> str:
+        """Generate a secure random token for this auth source.
+
+        Returns a URL-safe random token. If a prefix is configured it is
+        prepended — the returned value is what you store in your database
+        and return to the client as-is.
+
+        Args:
+            nbytes: Number of random bytes before base64 encoding. The
+                resulting string is ``ceil(nbytes * 4 / 3)`` characters
+                (43 chars for the default 32 bytes). Defaults to 32.
+
+        Returns:
+            A ready-to-use token string (e.g. ``"user_Xk3..."``).
+
+        Example::
+
+            bearer = BearerTokenAuth(verify_token, prefix="user_")
+            token = bearer.generate_token()   # "user_<random>"
+            await db.store_token(user_id, token)
+            return {"access_token": token, "token_type": "bearer"}
+        """
+        token = secrets.token_urlsafe(nbytes)
+        if self._prefix is not None:
+            return f"{self._prefix}{token}"
+        return token
diff --git a/src/fastapi_toolsets/security/sources/cookie.py b/src/fastapi_toolsets/security/sources/cookie.py
new file mode 100644
index 0000000..37eb9c2
--- /dev/null
+++ b/src/fastapi_toolsets/security/sources/cookie.py
@@ -0,0 +1,94 @@
+"""Cookie-based authentication source."""
+
+import inspect
+from typing import Annotated, Any, Callable
+
+from fastapi import Depends, Request
+from fastapi.security import APIKeyCookie, SecurityScopes
+
+from fastapi_toolsets.exceptions import UnauthorizedError
+
+from ..base import AuthSource
+
+
+class CookieAuth(AuthSource):
+    """Cookie-based authentication source.
+
+    Wraps :class:`fastapi.security.APIKeyCookie` for OpenAPI documentation.
+
+    Args:
+        name: Cookie name to read the credential from.
+        validator: Async callable that receives the cookie value and any extra
+            keyword arguments, and returns the authenticated identity.
+        **kwargs: Extra keyword arguments forwarded to the validator on every
+            call.
+
+    Example::
+
+        async def verify_session(session_id: str) -> User:
+            user = await db.get_by_session(session_id)
+            if not user:
+                raise UnauthorizedError()
+            return user
+
+        cookie_auth = CookieAuth("session", verify_session)
+
+        @app.get("/me")
+        async def me(user: User = Security(cookie_auth)):
+            return user
+    """
+
+    def __init__(
+        self,
+        name: str,
+        validator: Callable[..., Any],
+        **kwargs: Any,
+    ) -> None:
+        self._name = name
+        self._validator = validator
+        self._kwargs = kwargs
+        self._scheme = APIKeyCookie(name=name, auto_error=False)
+
+        _scheme = self._scheme
+        _validator = validator
+        _kwargs = kwargs
+
+        async def _call(
+            security_scopes: SecurityScopes,  # noqa: ARG001
+            value: Annotated[str | None, Depends(_scheme)] = None,
+        ) -> Any:
+            if value is None:
+                raise UnauthorizedError()
+            return await _validator(value, **_kwargs)
+
+        self._call_fn = _call
+        self.__signature__ = inspect.signature(_call)
+
+    async def __call__(self, **kwargs: Any) -> Any:
+        return await self._call_fn(**kwargs)
+
+    async def extract(self, request: Request) -> str | None:
+        """Extract the cookie value from the request without validating."""
+        return request.cookies.get(self._name)
+
+    async def authenticate(self, credential: str) -> Any:
+        """Validate a credential and return the identity."""
+        return await self._validator(credential, **self._kwargs)
+
+    def require(self, **kwargs: Any) -> "CookieAuth":
+        """Return a new instance with additional (or overriding) validator kwargs.
+
+        The cookie name is preserved. New kwargs are merged over existing ones
+        (new values win on conflict)::
+
+            cookie = CookieAuth("session", verify_session)
+
+            @app.get("/admin")
+            async def admin(user: User = Security(cookie.require(role=Role.ADMIN))):
+                return user
+        """
+        return CookieAuth(
+            self._name,
+            self._validator,
+            **{**self._kwargs, **kwargs},
+        )
diff --git a/src/fastapi_toolsets/security/sources/oauth2.py b/src/fastapi_toolsets/security/sources/oauth2.py
new file mode 100644
index 0000000..e515747
--- /dev/null
+++ b/src/fastapi_toolsets/security/sources/oauth2.py
@@ -0,0 +1,96 @@
+"""OAuth2 password-bearer authentication source."""
+
+import inspect
+from typing import Annotated, Any, Callable
+
+from fastapi import Depends, Request
+from fastapi.security import OAuth2PasswordBearer, SecurityScopes
+
+from fastapi_toolsets.exceptions import UnauthorizedError
+
+from ..base import AuthSource
+
+
+class OAuth2Auth(AuthSource):
+    """OAuth2 password-bearer authentication source.
+
+    Wraps :class:`fastapi.security.OAuth2PasswordBearer` for OpenAPI
+    documentation.
+
+    Args:
+        token_url: URL of the token endpoint (used in OpenAPI docs).
+        validator: Async callable that receives the token and any extra keyword
+            arguments, and returns the authenticated identity.
+        **kwargs: Extra keyword arguments forwarded to the validator on every
+            call.
+
+    Example::
+
+        async def verify_token(token: str) -> User:
+            ...
+
+        oauth2_auth = OAuth2Auth(token_url="/token", validator=verify_token)
+
+        @app.get("/me")
+        async def me(user: User = Security(oauth2_auth)):
+            return user
+    """
+
+    def __init__(
+        self,
+        token_url: str,
+        validator: Callable[..., Any],
+        **kwargs: Any,
+    ) -> None:
+        self._token_url = token_url
+        self._validator = validator
+        self._kwargs = kwargs
+        self._scheme = OAuth2PasswordBearer(tokenUrl=token_url, auto_error=False)
+
+        _scheme = self._scheme
+        _validator = validator
+        _kwargs = kwargs
+
+        async def _call(
+            security_scopes: SecurityScopes,  # noqa: ARG001
+            token: Annotated[str | None, Depends(_scheme)] = None,
+        ) -> Any:
+            if token is None:
+                raise UnauthorizedError()
+            return await _validator(token, **_kwargs)
+
+        self._call_fn = _call
+        self.__signature__ = inspect.signature(_call)
+
+    async def __call__(self, **kwargs: Any) -> Any:
+        return await self._call_fn(**kwargs)
+
+    async def extract(self, request: Request) -> str | None:
+        """Extract the bearer token from the Authorization header."""
+        auth = request.headers.get("Authorization", "")
+        if not auth.startswith("Bearer "):
+            return None
+        token = auth[7:]
+        return token or None
+
+    async def authenticate(self, credential: str) -> Any:
+        """Validate a credential and return the identity."""
+        return await self._validator(credential, **self._kwargs)
+
+    def require(self, **kwargs: Any) -> "OAuth2Auth":
+        """Return a new instance with additional (or overriding) validator kwargs.
+
+        The token URL is preserved. New kwargs are merged over existing ones
+        (new values win on conflict)::
+
+            oauth2 = OAuth2Auth("/token", verify_token)
+
+            @app.get("/admin")
+            async def admin(user: User = Security(oauth2.require(role=Role.ADMIN))):
+                return user
+        """
+        return OAuth2Auth(
+            self._token_url,
+            self._validator,
+            **{**self._kwargs, **kwargs},
+        )
diff --git a/src/fastapi_toolsets/security/sources/openid.py b/src/fastapi_toolsets/security/sources/openid.py
new file mode 100644
index 0000000..e12d887
--- /dev/null
+++ b/src/fastapi_toolsets/security/sources/openid.py
@@ -0,0 +1,127 @@
+"""OpenID Connect authentication source."""
+
+import inspect
+from typing import Annotated, Any, Callable
+
+from fastapi import Depends, Request
+from fastapi.security import OpenIdConnect, SecurityScopes
+
+from fastapi_toolsets.exceptions import UnauthorizedError
+
+from ..base import AuthSource
+
+
+class OpenIDAuth(AuthSource):
+    """OpenID Connect authentication source.
+
+    Wraps :class:`fastapi.security.OpenIdConnect` for OpenAPI documentation.
+    Token extraction reads the ``Authorization: Bearer <token>`` header;
+    validation is fully delegated to the user-supplied validator (use any
+    OIDC / JWT library such as ``authlib``, ``python-jose``, or ``PyJWT``).
+
+    Args:
+        openid_connect_url: URL of the OIDC discovery document
+            (``/.well-known/openid-configuration``). Used only for OpenAPI
+            documentation — no requests are made to this URL by this class.
+        validator: Async callable that receives the raw bearer token and any
+            extra keyword arguments, and returns the authenticated identity.
+            Should raise :class:`~fastapi_toolsets.exceptions.UnauthorizedError`
+            on failure.
+        **kwargs: Extra keyword arguments forwarded to the validator on every
+            call (e.g. ``audience="my-app"``).
+
+    Example — Google::
+
+        import jwt  # e.g. PyJWT or python-jose
+
+        async def verify_google_token(token: str, *, audience: str) -> User:
+            payload = jwt.decode(token, google_public_keys, algorithms=["RS256"],
+                                 audience=audience)
+            return User(email=payload["email"], name=payload["name"])
+
+        google_auth = OpenIDAuth(
+            "https://accounts.google.com/.well-known/openid-configuration",
+            verify_google_token,
+            audience="my-client-id",
+        )
+
+        @app.get("/me")
+        async def me(user: User = Security(google_auth)):
+            return user
+
+    Multiple providers with :func:`~fastapi_toolsets.security.MultiAuth`::
+
+        multi = MultiAuth(google_auth, github_auth)
+
+        @app.get("/data")
+        async def data(user: User = Security(multi)):
+            return user
+    """
+
+    def __init__(
+        self,
+        openid_connect_url: str,
+        validator: Callable[..., Any],
+        **kwargs: Any,
+    ) -> None:
+        self._openid_connect_url = openid_connect_url
+        self._validator = validator
+        self._kwargs = kwargs
+        self._scheme = OpenIdConnect(
+            openIdConnectUrl=openid_connect_url, auto_error=False
+        )
+
+        _scheme = self._scheme
+        _validator = validator
+        _kwargs = kwargs
+
+        async def _call(
+            security_scopes: SecurityScopes,  # noqa: ARG001
+            # OpenIdConnect (OAuth2 base) returns the full Authorization header
+            # value (e.g. "Bearer <token>"), unlike OAuth2PasswordBearer which
+            # strips the scheme prefix.
+            authorization: Annotated[str | None, Depends(_scheme)] = None,
+        ) -> Any:
+            if authorization is None:
+                raise UnauthorizedError()
+            if not authorization.startswith("Bearer "):
+                raise UnauthorizedError()
+            token = authorization[7:]
+            if not token:
+                raise UnauthorizedError()
+            return await _validator(token, **_kwargs)
+
+        self._call_fn = _call
+        self.__signature__ = inspect.signature(_call)
+
+    async def __call__(self, **kwargs: Any) -> Any:
+        return await self._call_fn(**kwargs)
+
+    async def extract(self, request: Request) -> str | None:
+        """Extract the bearer token from the Authorization header."""
+        auth = request.headers.get("Authorization", "")
+        if not auth.startswith("Bearer "):
+            return None
+        return auth[7:] or None
+
+    async def authenticate(self, credential: str) -> Any:
+        """Validate a credential and return the identity."""
+        return await self._validator(credential, **self._kwargs)
+
+    def require(self, **kwargs: Any) -> "OpenIDAuth":
+        """Return a new instance with additional (or overriding) validator kwargs.
+
+        The discovery URL is preserved. New kwargs are merged over existing ones
+        (new values win on conflict)::
+
+            google_auth = OpenIDAuth(discovery_url, verify_google_token, audience="app")
+
+            @app.get("/admin")
+            async def admin(user: User = Security(google_auth.require(role=Role.ADMIN))):
+                return user
+        """
+        return OpenIDAuth(
+            self._openid_connect_url,
+            self._validator,
+            **{**self._kwargs, **kwargs},
+        )
diff --git a/tests/test_security.py b/tests/test_security.py
new file mode 100644
index 0000000..2d3eac0
--- /dev/null
+++ b/tests/test_security.py
@@ -0,0 +1,902 @@
+"""Tests for fastapi_toolsets.security."""
+
+import pytest
+from fastapi import FastAPI, Security
+from fastapi.testclient import TestClient
+
+from fastapi_toolsets.exceptions import UnauthorizedError, init_exceptions_handlers
+from fastapi_toolsets.security import (
+    AuthSource,
+    BearerTokenAuth,
+    CookieAuth,
+    MultiAuth,
+    OAuth2Auth,
+    OpenIDAuth,
+)
+
+
+def _app(*routes_setup_fns):
+    """Build a minimal FastAPI test app with exception handlers."""
+    app = FastAPI()
+    init_exceptions_handlers(app)
+    for fn in routes_setup_fns:
+        fn(app)
+    return app
+
+
+VALID_TOKEN = "secret"
+VALID_COOKIE = "session123"
+
+
+async def simple_validator(credential: str) -> dict:
+    if credential != VALID_TOKEN:
+        raise UnauthorizedError()
+    return {"user": "alice"}
+
+
+async def role_validator(credential: str, *, role: str) -> dict:
+    if credential != VALID_TOKEN:
+        raise UnauthorizedError()
+    return {"user": "alice", "role": role}
+
+
+async def cookie_validator(value: str) -> dict:
+    if value != VALID_COOKIE:
+        raise UnauthorizedError()
+    return {"session": value}
+
+
+class TestBearerTokenAuth:
+    def test_valid_token_returns_identity(self):
+        bearer = BearerTokenAuth(simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+    def test_missing_header_returns_401(self):
+        bearer = BearerTokenAuth(simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me")
+        assert response.status_code == 401
+
+    def test_invalid_token_returns_401(self):
+        bearer = BearerTokenAuth(simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": "Bearer wrong"})
+        assert response.status_code == 401
+
+    def test_kwargs_forwarded_to_validator(self):
+        bearer = BearerTokenAuth(role_validator, role="admin")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+    def test_prefix_matching_passes_full_token(self):
+        """Token with matching prefix: full token (with prefix) is passed to validator."""
+        received: list[str] = []
+
+        async def capturing_validator(credential: str) -> dict:
+            received.append(credential)
+            return {"user": "alice"}
+
+        bearer = BearerTokenAuth(capturing_validator, prefix="user_")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": "Bearer user_abc123"})
+        assert response.status_code == 200
+        # Prefix is kept — validator receives the full token as stored in DB
+        assert received == ["user_abc123"]
+
+    def test_prefix_mismatch_returns_401(self):
+        bearer = BearerTokenAuth(simple_validator, prefix="user_")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": "Bearer org_abc123"})
+        assert response.status_code == 401
+
+    # --- extract() ---
+
+    @pytest.mark.anyio
+    async def test_extract_no_header(self):
+        from starlette.requests import Request
+
+        bearer = BearerTokenAuth(simple_validator)
+        scope = {"type": "http", "method": "GET", "path": "/", "headers": []}
+        request = Request(scope)
+        assert await bearer.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_empty_token(self):
+        from starlette.requests import Request
+
+        bearer = BearerTokenAuth(simple_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer ")],
+        }
+        request = Request(scope)
+        assert await bearer.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_no_prefix(self):
+        from starlette.requests import Request
+
+        bearer = BearerTokenAuth(simple_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer mytoken")],
+        }
+        request = Request(scope)
+        assert await bearer.extract(request) == "mytoken"
+
+    @pytest.mark.anyio
+    async def test_extract_prefix_match(self):
+        from starlette.requests import Request
+
+        bearer = BearerTokenAuth(simple_validator, prefix="user_")
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer user_abc")],
+        }
+        request = Request(scope)
+        assert await bearer.extract(request) == "user_abc"
+
+    @pytest.mark.anyio
+    async def test_extract_prefix_no_match(self):
+        from starlette.requests import Request
+
+        bearer = BearerTokenAuth(simple_validator, prefix="user_")
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer org_abc")],
+        }
+        request = Request(scope)
+        assert await bearer.extract(request) is None
+
+    # --- generate_token() ---
+
+    def test_generate_token_no_prefix(self):
+        bearer = BearerTokenAuth(simple_validator)
+        token = bearer.generate_token()
+        assert isinstance(token, str)
+        assert len(token) > 0
+
+    def test_generate_token_with_prefix(self):
+        bearer = BearerTokenAuth(simple_validator, prefix="user_")
+        token = bearer.generate_token()
+        assert token.startswith("user_")
+
+    def test_generate_token_uniqueness(self):
+        bearer = BearerTokenAuth(simple_validator)
+        assert bearer.generate_token() != bearer.generate_token()
+
+    def test_generate_token_is_valid_credential(self):
+        """A generated token (with prefix) is accepted by the same auth source."""
+        stored: list[str] = []
+
+        async def storing_validator(credential: str) -> dict:
+            stored.append(credential)
+            return {"token": credential}
+
+        bearer = BearerTokenAuth(storing_validator, prefix="user_")
+        token = bearer.generate_token()
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(bearer)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {token}"})
+        assert response.status_code == 200
+        assert stored == [token]
+
+
+class TestCookieAuth:
+    def test_valid_cookie_returns_identity(self):
+        cookie_auth = CookieAuth("session", cookie_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(cookie_auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", cookies={"session": VALID_COOKIE})
+        assert response.status_code == 200
+        assert response.json() == {"session": VALID_COOKIE}
+
+    def test_missing_cookie_returns_401(self):
+        cookie_auth = CookieAuth("session", cookie_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(cookie_auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me")
+        assert response.status_code == 401
+
+    def test_invalid_cookie_returns_401(self):
+        cookie_auth = CookieAuth("session", cookie_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(cookie_auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", cookies={"session": "wrong"})
+        assert response.status_code == 401
+
+    def test_kwargs_forwarded_to_validator(self):
+        async def session_validator(value: str, *, scope: str) -> dict:
+            if value != VALID_COOKIE:
+                raise UnauthorizedError()
+            return {"session": value, "scope": scope}
+
+        cookie_auth = CookieAuth("session", session_validator, scope="read")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(cookie_auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", cookies={"session": VALID_COOKIE})
+        assert response.status_code == 200
+        assert response.json() == {"session": VALID_COOKIE, "scope": "read"}
+
+    @pytest.mark.anyio
+    async def test_extract_no_cookie(self):
+        from starlette.requests import Request
+
+        auth = CookieAuth("session", cookie_validator)
+        scope = {"type": "http", "method": "GET", "path": "/", "headers": []}
+        request = Request(scope)
+        assert await auth.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_cookie_present(self):
+        from starlette.requests import Request
+
+        auth = CookieAuth("session", cookie_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"cookie", b"session=abc")],
+        }
+        request = Request(scope)
+        assert await auth.extract(request) == "abc"
+
+
+class TestOAuth2Auth:
+    def test_valid_token_returns_identity(self):
+        oauth = OAuth2Auth(token_url="/token", validator=simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(oauth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+    def test_missing_token_returns_401(self):
+        oauth = OAuth2Auth(token_url="/token", validator=simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(oauth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me")
+        assert response.status_code == 401
+
+    @pytest.mark.anyio
+    async def test_extract_no_header(self):
+        from starlette.requests import Request
+
+        auth = OAuth2Auth("/token", simple_validator)
+        scope = {"type": "http", "method": "GET", "path": "/", "headers": []}
+        request = Request(scope)
+        assert await auth.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_empty_token(self):
+        from starlette.requests import Request
+
+        auth = OAuth2Auth("/token", simple_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer ")],
+        }
+        request = Request(scope)
+        assert await auth.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_token(self):
+        from starlette.requests import Request
+
+        auth = OAuth2Auth("/token", simple_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer mytoken")],
+        }
+        request = Request(scope)
+        assert await auth.extract(request) == "mytoken"
+
+    def test_in_multi_auth(self):
+        """OAuth2Auth.authenticate() is exercised when used inside MultiAuth."""
+        oauth = OAuth2Auth(token_url="/token", validator=simple_validator)
+        multi = MultiAuth(oauth)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+
+class TestMultiAuth:
+    def test_first_source_matches(self):
+        bearer = BearerTokenAuth(simple_validator)
+        cookie = CookieAuth("session", cookie_validator)
+        multi = MultiAuth(bearer, cookie)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+    def test_second_source_matches_when_first_absent(self):
+        bearer = BearerTokenAuth(simple_validator)
+        cookie = CookieAuth("session", cookie_validator)
+        multi = MultiAuth(bearer, cookie)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        # No Authorization header — falls through to cookie
+        response = client.get("/me", cookies={"session": VALID_COOKIE})
+        assert response.status_code == 200
+        assert response.json() == {"session": VALID_COOKIE}
+
+    def test_no_source_matches_returns_401(self):
+        bearer = BearerTokenAuth(simple_validator)
+        cookie = CookieAuth("session", cookie_validator)
+        multi = MultiAuth(bearer, cookie)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me")
+        assert response.status_code == 401
+
+    def test_invalid_credential_does_not_fallthrough(self):
+        """If a credential is found but invalid, the next source is NOT tried."""
+        second_called: list[bool] = []
+
+        async def tracking_validator(credential: str) -> dict:
+            second_called.append(True)
+            return {"from": "second"}
+
+        bearer = BearerTokenAuth(simple_validator)  # raises on wrong token
+        cookie = CookieAuth("session", tracking_validator)
+        multi = MultiAuth(bearer, cookie)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        # Bearer credential present but wrong — should NOT try cookie
+        response = client.get(
+            "/me",
+            headers={"Authorization": "Bearer wrong"},
+            cookies={"session": VALID_COOKIE},
+        )
+        assert response.status_code == 401
+        assert second_called == []  # cookie validator was never called
+
+    def test_prefix_routes_to_correct_source(self):
+        """Prefix-based dispatch: only the matching source's validator is called."""
+        user_calls: list[str] = []
+        org_calls: list[str] = []
+
+        async def user_validator(credential: str) -> dict:
+            user_calls.append(credential)
+            return {"type": "user", "id": credential}
+
+        async def org_validator(credential: str) -> dict:
+            org_calls.append(credential)
+            return {"type": "org", "id": credential}
+
+        user_bearer = BearerTokenAuth(user_validator, prefix="user_")
+        org_bearer = BearerTokenAuth(org_validator, prefix="org_")
+        multi = MultiAuth(user_bearer, org_bearer)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+
+        response = client.get("/me", headers={"Authorization": "Bearer user_alice"})
+        assert response.status_code == 200
+        assert response.json() == {"type": "user", "id": "user_alice"}
+        assert user_calls == ["user_alice"]
+        assert org_calls == []
+
+        user_calls.clear()
+
+        response = client.get("/me", headers={"Authorization": "Bearer org_acme"})
+        assert response.status_code == 200
+        assert response.json() == {"type": "org", "id": "org_acme"}
+        assert user_calls == []
+        assert org_calls == ["org_acme"]
+
+    def test_require_returns_new_multi_auth(self):
+        from fastapi_toolsets.security.multi import MultiAuth as MultiAuthClass
+
+        bearer = BearerTokenAuth(role_validator)
+        multi = MultiAuth(bearer)
+        derived = multi.require(role="admin")
+        assert isinstance(derived, MultiAuthClass)
+        assert derived is not multi
+
+    def test_require_forwards_kwargs_to_sources(self):
+        """multi.require() propagates to all sources that support it."""
+        bearer = BearerTokenAuth(role_validator)
+        multi = MultiAuth(bearer)
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(multi.require(role="admin"))):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get(
+            "/admin", headers={"Authorization": f"Bearer {VALID_TOKEN}"}
+        )
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+    def test_require_skips_sources_without_require(self):
+        """Sources without require() are passed through unchanged."""
+        header_auth = _HeaderAuth(secret="s3cr3t")
+        multi = MultiAuth(header_auth)
+        derived = multi.require(role="admin")
+        assert derived._sources[0] is header_auth
+
+    def test_require_does_not_mutate_original(self):
+        bearer = BearerTokenAuth(role_validator, role="user")
+        multi = MultiAuth(bearer)
+        multi.require(role="admin")
+        assert bearer._kwargs == {"role": "user"}
+
+    def test_require_mixed_sources(self):
+        """require() applies to sources with require(), skips those without."""
+        from typing import cast
+
+        bearer = BearerTokenAuth(role_validator)
+        header_auth = _HeaderAuth(secret="s3cr3t")
+        multi = MultiAuth(bearer, header_auth)
+        derived = multi.require(role="admin")
+        # bearer got require() applied, header_auth passed through
+        assert cast(BearerTokenAuth, derived._sources[0])._kwargs == {"role": "admin"}
+        assert derived._sources[1] is header_auth
+
+
+class TestRequire:
+    def test_bearer_require_forwards_kwargs(self):
+        """require() creates a new instance that passes merged kwargs to validator."""
+        bearer = BearerTokenAuth(role_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(bearer.require(role="admin"))):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get(
+            "/admin", headers={"Authorization": f"Bearer {VALID_TOKEN}"}
+        )
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+    def test_bearer_require_overrides_existing_kwarg(self):
+        """require() kwargs override kwargs set at instantiation."""
+        bearer = BearerTokenAuth(role_validator, role="user")
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(bearer.require(role="admin"))):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get(
+            "/admin", headers={"Authorization": f"Bearer {VALID_TOKEN}"}
+        )
+        assert response.status_code == 200
+        assert response.json()["role"] == "admin"
+
+    def test_bearer_require_preserves_prefix(self):
+        """require() keeps the prefix of the original instance."""
+        bearer = BearerTokenAuth(role_validator, prefix="user_")
+        derived = bearer.require(role="admin")
+        assert derived._prefix == "user_"
+
+    def test_bearer_require_does_not_mutate_original(self):
+        """require() returns a new instance — original kwargs are unchanged."""
+        bearer = BearerTokenAuth(role_validator, role="user")
+        bearer.require(role="admin")
+        assert bearer._kwargs == {"role": "user"}
+
+    def test_cookie_require_forwards_kwargs(self):
+        async def scoped_validator(value: str, *, scope: str) -> dict:
+            if value != VALID_COOKIE:
+                raise UnauthorizedError()
+            return {"session": value, "scope": scope}
+
+        cookie = CookieAuth("session", scoped_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(cookie.require(scope="admin"))):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/admin", cookies={"session": VALID_COOKIE})
+        assert response.status_code == 200
+        assert response.json() == {"session": VALID_COOKIE, "scope": "admin"}
+
+    def test_cookie_require_preserves_name(self):
+        cookie = CookieAuth("session", cookie_validator)
+        derived = cookie.require(scope="admin")
+        assert derived._name == "session"
+
+    def test_oauth2_require_forwards_kwargs(self):
+        oauth = OAuth2Auth("/token", role_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(oauth.require(role="admin"))):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get(
+            "/admin", headers={"Authorization": f"Bearer {VALID_TOKEN}"}
+        )
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+    def test_oauth2_require_preserves_token_url(self):
+        oauth = OAuth2Auth("/token", simple_validator)
+        derived = oauth.require(role="admin")
+        assert derived._token_url == "/token"
+
+    def test_bearer_require_in_multi_auth(self):
+        """require() instances work seamlessly inside MultiAuth."""
+        PREFIXED_TOKEN = f"user_{VALID_TOKEN}"
+
+        async def prefixed_role_validator(credential: str, *, role: str) -> dict:
+            if credential != PREFIXED_TOKEN:
+                raise UnauthorizedError()
+            return {"user": "alice", "role": role}
+
+        bearer = BearerTokenAuth(prefixed_role_validator, prefix="user_")
+        multi = MultiAuth(bearer.require(role="admin"))
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get(
+            "/admin", headers={"Authorization": f"Bearer {PREFIXED_TOKEN}"}
+        )
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+
+class TestOpenIDAuth:
+    DISCOVERY_URL = "https://accounts.example.com/.well-known/openid-configuration"
+
+    def test_valid_token_returns_identity(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(oidc)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+    def test_missing_token_returns_401(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(oidc)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me")
+        assert response.status_code == 401
+
+    def test_invalid_token_returns_401(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(oidc)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": "Bearer wrong"})
+        assert response.status_code == 401
+
+    def test_kwargs_forwarded_to_validator(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, role_validator, role="admin")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(oidc)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+    def test_require_forwards_kwargs(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, role_validator)
+
+        def setup(app: FastAPI):
+            @app.get("/admin")
+            async def admin(user=Security(oidc.require(role="admin"))):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get(
+            "/admin", headers={"Authorization": f"Bearer {VALID_TOKEN}"}
+        )
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice", "role": "admin"}
+
+    def test_require_preserves_discovery_url(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+        derived = oidc.require(role="admin")
+        assert derived._openid_connect_url == self.DISCOVERY_URL
+
+    def test_require_does_not_mutate_original(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, role_validator, role="user")
+        oidc.require(role="admin")
+        assert oidc._kwargs == {"role": "user"}
+
+    def test_is_auth_source(self):
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+        assert isinstance(oidc, AuthSource)
+
+    def test_in_multi_auth(self):
+        """OpenIDAuth works seamlessly inside MultiAuth."""
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+        multi = MultiAuth(oidc)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+    @pytest.mark.anyio
+    async def test_extract_no_header(self):
+        from starlette.requests import Request
+
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+        scope = {"type": "http", "method": "GET", "path": "/", "headers": []}
+        request = Request(scope)
+        assert await oidc.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_empty_token(self):
+        from starlette.requests import Request
+
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer ")],
+        }
+        request = Request(scope)
+        assert await oidc.extract(request) is None
+
+    @pytest.mark.anyio
+    async def test_extract_token(self):
+        from starlette.requests import Request
+
+        oidc = OpenIDAuth(self.DISCOVERY_URL, simple_validator)
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/",
+            "headers": [(b"authorization", b"Bearer mytoken")],
+        }
+        request = Request(scope)
+        assert await oidc.extract(request) == "mytoken"
+
+
+# Minimal concrete subclass used only in tests below.
+class _HeaderAuth(AuthSource):
+    """Reads a custom X-Token header — no FastAPI security scheme."""
+
+    def __init__(self, secret: str) -> None:
+        super().__init__()
+        self._secret = secret
+
+    async def extract(self, request) -> str | None:
+        return request.headers.get("X-Token") or None
+
+    async def authenticate(self, credential: str) -> dict:
+        if credential != self._secret:
+            raise UnauthorizedError()
+        return {"token": credential}
+
+
+class TestAuthSource:
+    def test_cannot_instantiate_abstract_class(self):
+        with pytest.raises(TypeError):
+            AuthSource()
+
+    def test_builtin_classes_are_auth_sources(self):
+        bearer = BearerTokenAuth(simple_validator)
+        cookie = CookieAuth("session", cookie_validator)
+        oauth = OAuth2Auth("/token", simple_validator)
+        oidc = OpenIDAuth(
+            "https://example.com/.well-known/openid-configuration", simple_validator
+        )
+        assert isinstance(bearer, AuthSource)
+        assert isinstance(cookie, AuthSource)
+        assert isinstance(oauth, AuthSource)
+        assert isinstance(oidc, AuthSource)
+
+    def test_custom_source_standalone_valid(self):
+        """Default __call__ wires extract + authenticate via Request injection."""
+        auth = _HeaderAuth(secret="s3cr3t")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"X-Token": "s3cr3t"})
+        assert response.status_code == 200
+        assert response.json() == {"token": "s3cr3t"}
+
+    def test_custom_source_standalone_missing_credential(self):
+        auth = _HeaderAuth(secret="s3cr3t")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me")  # no X-Token header
+        assert response.status_code == 401
+
+    def test_custom_source_standalone_invalid_credential(self):
+        auth = _HeaderAuth(secret="s3cr3t")
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(auth)):
+                return user
+
+        client = TestClient(_app(setup))
+        response = client.get("/me", headers={"X-Token": "wrong"})
+        assert response.status_code == 401
+
+    def test_custom_source_in_multi_auth(self):
+        """Custom AuthSource works transparently inside MultiAuth."""
+        header_auth = _HeaderAuth(secret="s3cr3t")
+        bearer = BearerTokenAuth(simple_validator)
+        multi = MultiAuth(bearer, header_auth)
+
+        def setup(app: FastAPI):
+            @app.get("/me")
+            async def me(user=Security(multi)):
+                return user
+
+        client = TestClient(_app(setup))
+
+        # Bearer matches first
+        response = client.get("/me", headers={"Authorization": f"Bearer {VALID_TOKEN}"})
+        assert response.status_code == 200
+        assert response.json() == {"user": "alice"}
+
+        # No bearer → falls through to custom header source
+        response = client.get("/me", headers={"X-Token": "s3cr3t"})
+        assert response.status_code == 200
+        assert response.json() == {"token": "s3cr3t"}