diff --git a/fastapi_users/authentication/authenticator.py b/fastapi_users/authentication/authenticator.py
index 41f297d5..7fab4b78 100644
--- a/fastapi_users/authentication/authenticator.py
+++ b/fastapi_users/authentication/authenticator.py
@@ -51,7 +51,7 @@ class Authenticator:
     def __init__(
         self,
         backends: Sequence[AuthenticationBackend],
-        get_user_manager: UserManagerDependency[models.UP],
+        get_user_manager: UserManagerDependency[models.UP, models.ID],
     ):
         self.backends = backends
         self.get_user_manager = get_user_manager
@@ -148,7 +148,7 @@ class Authenticator:
     async def _authenticate(
         self,
         *args,
-        user_manager: BaseUserManager[models.UP],
+        user_manager: BaseUserManager[models.UP, models.ID],
         optional: bool = False,
         active: bool = False,
         verified: bool = False,
@@ -163,7 +163,7 @@ class Authenticator:
         for backend in self.backends:
             if backend in enabled_backends:
                 token = kwargs[name_to_variable_name(backend.name)]
-                strategy: Strategy[models.UP] = kwargs[
+                strategy: Strategy[models.UP, models.ID] = kwargs[
                     name_to_strategy_variable_name(backend.name)
                 ]
                 if token is not None:
diff --git a/fastapi_users/authentication/backend.py b/fastapi_users/authentication/backend.py
index f4931c75..09861210 100644
--- a/fastapi_users/authentication/backend.py
+++ b/fastapi_users/authentication/backend.py
@@ -33,7 +33,7 @@ class AuthenticationBackend(Generic[models.UP]):
         self,
         name: str,
         transport: Transport,
-        get_strategy: DependencyCallable[Strategy[models.UP]],
+        get_strategy: DependencyCallable[Strategy[models.UP, models.ID]],
     ):
         self.name = name
         self.transport = transport
@@ -41,7 +41,7 @@ class AuthenticationBackend(Generic[models.UP]):
 
     async def login(
         self,
-        strategy: Strategy[models.UP],
+        strategy: Strategy[models.UP, models.ID],
         user: models.UP,
         response: Response,
     ) -> Any:
@@ -50,7 +50,7 @@ class AuthenticationBackend(Generic[models.UP]):
 
     async def logout(
         self,
-        strategy: Strategy[models.UP],
+        strategy: Strategy[models.UP, models.ID],
         user: models.UP,
         token: str,
         response: Response,
diff --git a/fastapi_users/authentication/strategy/base.py b/fastapi_users/authentication/strategy/base.py
index 6954cec0..ce60db13 100644
--- a/fastapi_users/authentication/strategy/base.py
+++ b/fastapi_users/authentication/strategy/base.py
@@ -14,9 +14,9 @@ class StrategyDestroyNotSupportedError(Exception):
     pass
 
 
-class Strategy(Protocol, Generic[models.UP]):
+class Strategy(Protocol, Generic[models.UP, models.ID]):
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         ...  # pragma: no cover
 
diff --git a/fastapi_users/authentication/strategy/db/models.py b/fastapi_users/authentication/strategy/db/models.py
index 810d0a5d..6c3b58be 100644
--- a/fastapi_users/authentication/strategy/db/models.py
+++ b/fastapi_users/authentication/strategy/db/models.py
@@ -1,5 +1,4 @@
 import sys
-import uuid
 from datetime import datetime
 from typing import TypeVar
 
@@ -8,12 +7,14 @@ if sys.version_info < (3, 8):
 else:
     from typing import Protocol  # pragma: no cover
 
+from fastapi_users import models
 
-class AccessTokenProtocol(Protocol):
+
+class AccessTokenProtocol(Protocol[models.ID]):
     """Access token protocol that ORM model should follow."""
 
     token: str
-    user_id: uuid.UUID
+    user_id: models.ID
     created_at: datetime
 
     def __init__(self, *args, **kwargs) -> None:
diff --git a/fastapi_users/authentication/strategy/db/strategy.py b/fastapi_users/authentication/strategy/db/strategy.py
index ce4998c8..e3cb93df 100644
--- a/fastapi_users/authentication/strategy/db/strategy.py
+++ b/fastapi_users/authentication/strategy/db/strategy.py
@@ -6,7 +6,7 @@ from fastapi_users import models
 from fastapi_users.authentication.strategy.base import Strategy
 from fastapi_users.authentication.strategy.db.adapter import AccessTokenDatabase
 from fastapi_users.authentication.strategy.db.models import AP
-from fastapi_users.manager import BaseUserManager, UserNotExists
+from fastapi_users.manager import BaseUserManager, InvalidID, UserNotExists
 
 
 class DatabaseStrategy(Strategy, Generic[models.UP, AP]):
@@ -17,7 +17,7 @@ class DatabaseStrategy(Strategy, Generic[models.UP, AP]):
         self.lifetime_seconds = lifetime_seconds
 
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         if token is None:
             return None
@@ -33,9 +33,9 @@ class DatabaseStrategy(Strategy, Generic[models.UP, AP]):
             return None
 
         try:
-            user_id = access_token.user_id
-            return await user_manager.get(user_id)
-        except UserNotExists:
+            parsed_id = user_manager.parse_id(access_token.user_id)
+            return await user_manager.get(parsed_id)
+        except (UserNotExists, InvalidID):
             return None
 
     async def write_token(self, user: models.UP) -> str:
diff --git a/fastapi_users/authentication/strategy/jwt.py b/fastapi_users/authentication/strategy/jwt.py
index 38ebe77f..a2fbf58e 100644
--- a/fastapi_users/authentication/strategy/jwt.py
+++ b/fastapi_users/authentication/strategy/jwt.py
@@ -1,7 +1,6 @@
 from typing import Generic, List, Optional
 
 import jwt
-from pydantic import UUID4
 
 from fastapi_users import models
 from fastapi_users.authentication.strategy.base import (
@@ -9,7 +8,7 @@ from fastapi_users.authentication.strategy.base import (
     StrategyDestroyNotSupportedError,
 )
 from fastapi_users.jwt import SecretType, decode_jwt, generate_jwt
-from fastapi_users.manager import BaseUserManager, UserNotExists
+from fastapi_users.manager import BaseUserManager, InvalidID, UserNotExists
 
 
 class JWTStrategy(Strategy, Generic[models.UP]):
@@ -36,7 +35,7 @@ class JWTStrategy(Strategy, Generic[models.UP]):
         return self.public_key or self.secret
 
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         if token is None:
             return None
@@ -52,11 +51,9 @@ class JWTStrategy(Strategy, Generic[models.UP]):
             return None
 
         try:
-            user_uiid = UUID4(user_id)
-            return await user_manager.get(user_uiid)
-        except ValueError:
-            return None
-        except UserNotExists:
+            parsed_id = user_manager.parse_id(user_id)
+            return await user_manager.get(parsed_id)
+        except (UserNotExists, InvalidID):
             return None
 
     async def write_token(self, user: models.UP) -> str:
diff --git a/fastapi_users/authentication/strategy/redis.py b/fastapi_users/authentication/strategy/redis.py
index ce6a6a21..d6527892 100644
--- a/fastapi_users/authentication/strategy/redis.py
+++ b/fastapi_users/authentication/strategy/redis.py
@@ -2,11 +2,10 @@ import secrets
 from typing import Generic, Optional
 
 import aioredis
-from pydantic import UUID4
 
 from fastapi_users import models
 from fastapi_users.authentication.strategy.base import Strategy
-from fastapi_users.manager import BaseUserManager, UserNotExists
+from fastapi_users.manager import BaseUserManager, InvalidID, UserNotExists
 
 
 class RedisStrategy(Strategy, Generic[models.UP]):
@@ -15,7 +14,7 @@ class RedisStrategy(Strategy, Generic[models.UP]):
         self.lifetime_seconds = lifetime_seconds
 
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         if token is None:
             return None
@@ -25,11 +24,9 @@ class RedisStrategy(Strategy, Generic[models.UP]):
             return None
 
         try:
-            user_uiid = UUID4(user_id)
-            return await user_manager.get(user_uiid)
-        except ValueError:
-            return None
-        except UserNotExists:
+            parsed_id = user_manager.parse_id(user_id)
+            return await user_manager.get(parsed_id)
+        except (UserNotExists, InvalidID):
             return None
 
     async def write_token(self, user: models.UP) -> str:
diff --git a/fastapi_users/db/__init__.py b/fastapi_users/db/__init__.py
index 1856e059..d29c354b 100644
--- a/fastapi_users/db/__init__.py
+++ b/fastapi_users/db/__init__.py
@@ -1,9 +1,6 @@
 from fastapi_users.db.base import BaseUserDatabase, UserDatabaseDependency
 
-__all__ = [
-    "BaseUserDatabase",
-    "UserDatabaseDependency",
-]
+__all__ = ["BaseUserDatabase", "UserDatabaseDependency"]
 
 try:  # pragma: no cover
     from fastapi_users_db_mongodb import MongoDBUserDatabase  # noqa: F401
diff --git a/fastapi_users/db/base.py b/fastapi_users/db/base.py
index 6ac78730..681bad92 100644
--- a/fastapi_users/db/base.py
+++ b/fastapi_users/db/base.py
@@ -1,15 +1,13 @@
 from typing import Any, Dict, Generic, Optional
 
-from pydantic import UUID4
-
-from fastapi_users.models import OAP, UP
+from fastapi_users.models import ID, OAP, UP
 from fastapi_users.types import DependencyCallable
 
 
-class BaseUserDatabase(Generic[UP]):
+class BaseUserDatabase(Generic[UP, ID]):
     """Base adapter for retrieving, creating and updating users from a database."""
 
-    async def get(self, id: UUID4) -> Optional[UP]:
+    async def get(self, id: ID) -> Optional[UP]:
         """Get a single user by id."""
         raise NotImplementedError()
 
@@ -44,4 +42,4 @@ class BaseUserDatabase(Generic[UP]):
         raise NotImplementedError()
 
 
-UserDatabaseDependency = DependencyCallable[BaseUserDatabase[UP]]
+UserDatabaseDependency = DependencyCallable[BaseUserDatabase[UP, ID]]
diff --git a/fastapi_users/fastapi_users.py b/fastapi_users/fastapi_users.py
index 15517cdf..f784966d 100644
--- a/fastapi_users/fastapi_users.py
+++ b/fastapi_users/fastapi_users.py
@@ -44,7 +44,7 @@ class FastAPIUsers(Generic[models.UP, schemas.U, schemas.UC, schemas.UU]):
 
     def __init__(
         self,
-        get_user_manager: UserManagerDependency[models.UP],
+        get_user_manager: UserManagerDependency[models.UP, models.ID],
         auth_backends: Sequence[AuthenticationBackend],
         user_schema: Type[schemas.U],
         user_create_schema: Type[schemas.UC],
diff --git a/fastapi_users/manager.py b/fastapi_users/manager.py
index 77847561..116db23a 100644
--- a/fastapi_users/manager.py
+++ b/fastapi_users/manager.py
@@ -1,9 +1,9 @@
+import uuid
 from typing import Any, Dict, Generic, Optional, Union
 
 import jwt
 from fastapi import Request
 from fastapi.security import OAuth2PasswordRequestForm
-from pydantic import UUID4
 
 from fastapi_users import models, schemas
 from fastapi_users.db import BaseUserDatabase
@@ -19,6 +19,10 @@ class FastAPIUsersException(Exception):
     pass
 
 
+class InvalidID(FastAPIUsersException):
+    pass
+
+
 class UserAlreadyExists(FastAPIUsersException):
     pass
 
@@ -48,7 +52,7 @@ class InvalidPasswordException(FastAPIUsersException):
         self.reason = reason
 
 
-class BaseUserManager(Generic[models.UP]):
+class BaseUserManager(Generic[models.UP, models.ID]):
     """
     User management logic.
 
@@ -70,12 +74,12 @@ class BaseUserManager(Generic[models.UP]):
     verification_token_lifetime_seconds: int = 3600
     verification_token_audience: str = VERIFY_USER_TOKEN_AUDIENCE
 
-    user_db: BaseUserDatabase[models.UP]
+    user_db: BaseUserDatabase[models.UP, models.ID]
     password_helper: PasswordHelperProtocol
 
     def __init__(
         self,
-        user_db: BaseUserDatabase[models.UP],
+        user_db: BaseUserDatabase[models.UP, models.ID],
         password_helper: Optional[PasswordHelperProtocol] = None,
     ):
         self.user_db = user_db
@@ -84,7 +88,17 @@ class BaseUserManager(Generic[models.UP]):
         else:
             self.password_helper = password_helper  # pragma: no cover
 
-    async def get(self, id: UUID4) -> models.UP:
+    def parse_id(self, value: Any) -> models.ID:
+        """
+        Parse a value into a correct models.ID instance.
+
+        :param value: The value to parse.
+        :raises InvalidID: The models.ID value is invalid.
+        :return: An models.ID object.
+        """
+        raise NotImplementedError()  # pragma: no cover
+
+    async def get(self, id: models.ID) -> models.UP:
         """
         Get a user by id.
 
@@ -170,7 +184,7 @@ class BaseUserManager(Generic[models.UP]):
         return created_user
 
     async def oauth_callback(
-        self: "BaseUserManager[models.UOAP]",
+        self: "BaseUserManager[models.UOAP, models.ID]",
         oauth_name: str,
         access_token: str,
         account_id: str,
@@ -192,7 +206,7 @@ class BaseUserManager(Generic[models.UP]):
 
         :param oauth_name: Name of the OAuth client.
         :param access_token: Valid access token for the service provider.
-        :param account_id: ID of the user on the service provider.
+        :param account_id: models.ID of the user on the service provider.
         :param account_email: E-mail of the user on the service provider.
         :param expires_at: Optional timestamp at which the access token expires.
         :param refresh_token: Optional refresh token to get a
@@ -307,11 +321,11 @@ class BaseUserManager(Generic[models.UP]):
             raise InvalidVerifyToken()
 
         try:
-            user_uuid = UUID4(user_id)
-        except ValueError:
+            parsed_id = self.parse_id(user_id)
+        except InvalidID:
             raise InvalidVerifyToken()
 
-        if user_uuid != user.id:
+        if parsed_id != user.id:
             raise InvalidVerifyToken()
 
         if user.is_verified:
@@ -382,11 +396,11 @@ class BaseUserManager(Generic[models.UP]):
             raise InvalidResetPasswordToken()
 
         try:
-            user_uuid = UUID4(user_id)
-        except ValueError:
+            parsed_id = self.parse_id(user_id)
+        except InvalidID:
             raise InvalidResetPasswordToken()
 
-        user = await self.get(user_uuid)
+        user = await self.get(parsed_id)
 
         if not user.is_active:
             raise UserInactive()
@@ -588,4 +602,14 @@ class BaseUserManager(Generic[models.UP]):
         return await self.user_db.update(user, validated_update_dict)
 
 
-UserManagerDependency = DependencyCallable[BaseUserManager[models.UP]]
+class UUIDIDMixin:
+    def parse_id(self, value: Any) -> uuid.UUID:
+        if isinstance(value, uuid.UUID):
+            return value
+        try:
+            return uuid.UUID(value)
+        except ValueError as e:
+            raise InvalidID() from e
+
+
+UserManagerDependency = DependencyCallable[BaseUserManager[models.UP, models.ID]]
diff --git a/fastapi_users/models.py b/fastapi_users/models.py
index 37a9ff64..f6bbe1ab 100644
--- a/fastapi_users/models.py
+++ b/fastapi_users/models.py
@@ -1,5 +1,4 @@
 import sys
-import uuid
 from typing import Generic, List, Optional, TypeVar
 
 if sys.version_info < (3, 8):
@@ -7,11 +6,13 @@ if sys.version_info < (3, 8):
 else:
     from typing import Protocol  # pragma: no cover
 
+ID = TypeVar("ID")
 
-class UserProtocol(Protocol):
+
+class UserProtocol(Protocol[ID]):
     """User protocol that ORM model should follow."""
 
-    id: uuid.UUID
+    id: ID
     email: str
     hashed_password: str
     is_active: bool
@@ -22,10 +23,10 @@ class UserProtocol(Protocol):
         ...  # pragma: no cover
 
 
-class OAuthAccountProtocol(Protocol):
+class OAuthAccountProtocol(Protocol[ID]):
     """OAuth account protocol that ORM model should follow."""
 
-    id: uuid.UUID
+    id: ID
     oauth_name: str
     access_token: str
     expires_at: Optional[int]
@@ -41,7 +42,7 @@ UP = TypeVar("UP", bound=UserProtocol)
 OAP = TypeVar("OAP", bound=OAuthAccountProtocol)
 
 
-class UserOAuthProtocol(UserProtocol, Generic[OAP]):
+class UserOAuthProtocol(UserProtocol[ID], Generic[ID, OAP]):
     """User protocol including a list of OAuth accounts."""
 
     oauth_accounts: List[OAP]
diff --git a/fastapi_users/router/auth.py b/fastapi_users/router/auth.py
index 3fc1275f..cda0fa3e 100644
--- a/fastapi_users/router/auth.py
+++ b/fastapi_users/router/auth.py
@@ -12,7 +12,7 @@ from fastapi_users.router.common import ErrorCode, ErrorModel
 
 def get_auth_router(
     backend: AuthenticationBackend,
-    get_user_manager: UserManagerDependency[models.UP],
+    get_user_manager: UserManagerDependency[models.UP, models.ID],
     authenticator: Authenticator,
     requires_verification: bool = False,
 ) -> APIRouter:
@@ -51,8 +51,8 @@ def get_auth_router(
     async def login(
         response: Response,
         credentials: OAuth2PasswordRequestForm = Depends(),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
-        strategy: Strategy[models.UP] = Depends(backend.get_strategy),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
+        strategy: Strategy[models.UP, models.ID] = Depends(backend.get_strategy),
     ):
         user = await user_manager.authenticate(credentials)
 
@@ -83,7 +83,7 @@ def get_auth_router(
     async def logout(
         response: Response,
         user_token: Tuple[models.UP, str] = Depends(get_current_user_token),
-        strategy: Strategy[models.UP] = Depends(backend.get_strategy),
+        strategy: Strategy[models.UP, models.ID] = Depends(backend.get_strategy),
     ):
         user, token = user_token
         return await backend.logout(strategy, user, token, response)
diff --git a/fastapi_users/router/oauth.py b/fastapi_users/router/oauth.py
index 00499d2b..9ec1ac26 100644
--- a/fastapi_users/router/oauth.py
+++ b/fastapi_users/router/oauth.py
@@ -29,7 +29,7 @@ def generate_state_token(
 def get_oauth_router(
     oauth_client: BaseOAuth2,
     backend: AuthenticationBackend,
-    get_user_manager: UserManagerDependency[models.UP],
+    get_user_manager: UserManagerDependency[models.UP, models.ID],
     state_secret: SecretType,
     redirect_url: str = None,
 ) -> APIRouter:
@@ -101,8 +101,8 @@ def get_oauth_router(
         access_token_state: Tuple[OAuth2Token, str] = Depends(
             oauth2_authorize_callback
         ),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
-        strategy: Strategy[models.UP] = Depends(backend.get_strategy),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
+        strategy: Strategy[models.UP, models.ID] = Depends(backend.get_strategy),
     ):
         token, state = access_token_state
         account_id, account_email = await oauth_client.get_id_email(
diff --git a/fastapi_users/router/register.py b/fastapi_users/router/register.py
index 862b0406..3eab139e 100644
--- a/fastapi_users/router/register.py
+++ b/fastapi_users/router/register.py
@@ -13,7 +13,7 @@ from fastapi_users.router.common import ErrorCode, ErrorModel
 
 
 def get_register_router(
-    get_user_manager: UserManagerDependency[models.UP],
+    get_user_manager: UserManagerDependency[models.UP, models.ID],
     user_schema: Type[schemas.U],
     user_create_schema: Type[schemas.UC],
 ) -> APIRouter:
@@ -56,7 +56,7 @@ def get_register_router(
     async def register(
         request: Request,
         user_create: user_create_schema,  # type: ignore
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             created_user = await user_manager.create(
diff --git a/fastapi_users/router/reset.py b/fastapi_users/router/reset.py
index e6458321..95e2e93d 100644
--- a/fastapi_users/router/reset.py
+++ b/fastapi_users/router/reset.py
@@ -40,7 +40,7 @@ RESET_PASSWORD_RESPONSES: OpenAPIResponseType = {
 
 
 def get_reset_password_router(
-    get_user_manager: UserManagerDependency[models.UP],
+    get_user_manager: UserManagerDependency[models.UP, models.ID],
 ) -> APIRouter:
     """Generate a router with the reset password routes."""
     router = APIRouter()
@@ -53,7 +53,7 @@ def get_reset_password_router(
     async def forgot_password(
         request: Request,
         email: EmailStr = Body(..., embed=True),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             user = await user_manager.get_by_email(email)
@@ -76,7 +76,7 @@ def get_reset_password_router(
         request: Request,
         token: str = Body(...),
         password: str = Body(...),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             await user_manager.reset_password(token, password, request)
diff --git a/fastapi_users/router/users.py b/fastapi_users/router/users.py
index 9e744734..b6a48caf 100644
--- a/fastapi_users/router/users.py
+++ b/fastapi_users/router/users.py
@@ -1,12 +1,12 @@
-from typing import Type
+from typing import Any, Type
 
 from fastapi import APIRouter, Depends, HTTPException, Request, Response, status
-from pydantic import UUID4
 
 from fastapi_users import models, schemas
 from fastapi_users.authentication import Authenticator
 from fastapi_users.manager import (
     BaseUserManager,
+    InvalidID,
     InvalidPasswordException,
     UserAlreadyExists,
     UserManagerDependency,
@@ -16,7 +16,7 @@ from fastapi_users.router.common import ErrorCode, ErrorModel
 
 
 def get_users_router(
-    get_user_manager: UserManagerDependency[models.UP],
+    get_user_manager: UserManagerDependency[models.UP, models.ID],
     user_schema: Type[schemas.U],
     user_update_schema: Type[schemas.UU],
     authenticator: Authenticator,
@@ -33,13 +33,14 @@ def get_users_router(
     )
 
     async def get_user_or_404(
-        id: UUID4,
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        id: Any,
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ) -> models.UP:
         try:
-            return await user_manager.get(id)
-        except UserNotExists:
-            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND)
+            parsed_id = user_manager.parse_id(id)
+            return await user_manager.get(parsed_id)
+        except (UserNotExists, InvalidID) as e:
+            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND) from e
 
     @router.get(
         "/me",
@@ -96,7 +97,7 @@ def get_users_router(
         request: Request,
         user_update: user_update_schema,  # type: ignore
         user: models.UP = Depends(get_current_active_user),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             return await user_manager.update(
@@ -117,7 +118,7 @@ def get_users_router(
             )
 
     @router.get(
-        "/{id:uuid}",
+        "/{id}",
         response_model=user_schema,
         dependencies=[Depends(get_current_superuser)],
         name="users:user",
@@ -137,7 +138,7 @@ def get_users_router(
         return user
 
     @router.patch(
-        "/{id:uuid}",
+        "/{id}",
         response_model=user_schema,
         dependencies=[Depends(get_current_superuser)],
         name="users:patch_user",
@@ -182,7 +183,7 @@ def get_users_router(
         user_update: user_update_schema,  # type: ignore
         request: Request,
         user=Depends(get_user_or_404),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             return await user_manager.update(
@@ -203,7 +204,7 @@ def get_users_router(
             )
 
     @router.delete(
-        "/{id:uuid}",
+        "/{id}",
         status_code=status.HTTP_204_NO_CONTENT,
         response_class=Response,
         dependencies=[Depends(get_current_superuser)],
@@ -222,7 +223,7 @@ def get_users_router(
     )
     async def delete_user(
         user=Depends(get_user_or_404),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         await user_manager.delete(user)
         return None
diff --git a/fastapi_users/router/verify.py b/fastapi_users/router/verify.py
index 7860e18e..af6578f5 100644
--- a/fastapi_users/router/verify.py
+++ b/fastapi_users/router/verify.py
@@ -16,7 +16,7 @@ from fastapi_users.router.common import ErrorCode, ErrorModel
 
 
 def get_verify_router(
-    get_user_manager: UserManagerDependency[models.UP],
+    get_user_manager: UserManagerDependency[models.UP, models.ID],
     user_schema: Type[schemas.U],
 ):
     router = APIRouter()
@@ -29,7 +29,7 @@ def get_verify_router(
     async def request_verify_token(
         request: Request,
         email: EmailStr = Body(..., embed=True),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             user = await user_manager.get_by_email(email)
@@ -69,7 +69,7 @@ def get_verify_router(
     async def verify(
         request: Request,
         token: str = Body(..., embed=True),
-        user_manager: BaseUserManager[models.UP] = Depends(get_user_manager),
+        user_manager: BaseUserManager[models.UP, models.ID] = Depends(get_user_manager),
     ):
         try:
             return await user_manager.verify(token, request)
diff --git a/fastapi_users/schemas.py b/fastapi_users/schemas.py
index a361bd58..6ab2994d 100644
--- a/fastapi_users/schemas.py
+++ b/fastapi_users/schemas.py
@@ -1,7 +1,8 @@
-import uuid
-from typing import List, Optional, TypeVar
+from typing import Generic, List, Optional, TypeVar
 
-from pydantic import UUID4, BaseModel, EmailStr, Field
+from pydantic import BaseModel, EmailStr
+
+from fastapi_users import models
 
 
 class CreateUpdateDictModel(BaseModel):
@@ -21,10 +22,10 @@ class CreateUpdateDictModel(BaseModel):
         return self.dict(exclude_unset=True, exclude={"id"})
 
 
-class BaseUser(CreateUpdateDictModel):
+class BaseUser(Generic[models.ID], CreateUpdateDictModel):
     """Base User model."""
 
-    id: UUID4 = Field(default_factory=uuid.uuid4)
+    id: models.ID
     email: EmailStr
     is_active: bool = True
     is_superuser: bool = False
@@ -52,10 +53,10 @@ UC = TypeVar("UC", bound=BaseUserCreate)
 UU = TypeVar("UU", bound=BaseUserUpdate)
 
 
-class BaseOAuthAccount(BaseModel):
+class BaseOAuthAccount(Generic[models.ID], BaseModel):
     """Base OAuth account model."""
 
-    id: UUID4 = Field(default_factory=uuid.uuid4)
+    id: models.ID
     oauth_name: str
     access_token: str
     expires_at: Optional[int] = None
diff --git a/tests/conftest.py b/tests/conftest.py
index c995b13b..c998fa78 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -29,8 +29,10 @@ from fastapi_users.db import BaseUserDatabase
 from fastapi_users.jwt import SecretType
 from fastapi_users.manager import (
     BaseUserManager,
+    InvalidID,
     InvalidPasswordException,
     UserNotExists,
+    UUIDIDMixin,
 )
 from fastapi_users.openapi import OpenAPIResponseType
 from fastapi_users.password import PasswordHelper
@@ -43,8 +45,11 @@ lancelot_password_hash = password_helper.hash("lancelot")
 excalibur_password_hash = password_helper.hash("excalibur")
 
 
+IDType = uuid.UUID
+
+
 @dataclasses.dataclass
-class UserModel(models.UserProtocol):
+class UserModel(models.UserProtocol[IDType]):
     email: str
     hashed_password: str
     id: uuid.UUID = dataclasses.field(default_factory=uuid.uuid4)
@@ -55,7 +60,7 @@ class UserModel(models.UserProtocol):
 
 
 @dataclasses.dataclass
-class OAuthAccountModel(models.OAuthAccountProtocol):
+class OAuthAccountModel(models.OAuthAccountProtocol[IDType]):
     oauth_name: str
     access_token: str
     account_id: str
@@ -86,7 +91,9 @@ class UserOAuth(User, schemas.BaseOAuthAccountMixin):
     pass
 
 
-class BaseTestUserManager(Generic[models.UP], BaseUserManager[models.UP]):
+class BaseTestUserManager(
+    Generic[models.UP], UUIDIDMixin, BaseUserManager[models.UP, IDType]
+):
     reset_password_token_secret = "SECRET"
     verification_token_secret = "SECRET"
 
@@ -318,8 +325,8 @@ def mock_user_db(
     inactive_user: UserModel,
     superuser: UserModel,
     verified_superuser: UserModel,
-) -> BaseUserDatabase[UserModel]:
-    class MockUserDatabase(BaseUserDatabase[UserModel]):
+) -> BaseUserDatabase[UserModel, IDType]:
+    class MockUserDatabase(BaseUserDatabase[UserModel, IDType]):
         async def get(self, id: UUID4) -> Optional[UserModel]:
             if id == user.id:
                 return user
@@ -370,8 +377,8 @@ def mock_user_db_oauth(
     inactive_user_oauth: UserOAuthModel,
     superuser_oauth: UserOAuthModel,
     verified_superuser_oauth: UserOAuthModel,
-) -> BaseUserDatabase[UserOAuthModel]:
-    class MockUserDatabase(BaseUserDatabase[UserOAuthModel]):
+) -> BaseUserDatabase[UserOAuthModel, IDType]:
+    class MockUserDatabase(BaseUserDatabase[UserOAuthModel, IDType]):
         async def get(self, id: UUID4) -> Optional[UserOAuthModel]:
             if id == user_oauth.id:
                 return user_oauth
@@ -518,17 +525,15 @@ class MockTransport(BearerTransport):
         return {}
 
 
-class MockStrategy(Strategy[UserModel]):
+class MockStrategy(Strategy[UserModel, IDType]):
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[UserModel]
+        self, token: Optional[str], user_manager: BaseUserManager[UserModel, IDType]
     ) -> Optional[UserModel]:
         if token is not None:
             try:
-                token_uuid = UUID4(token)
-                return await user_manager.get(token_uuid)
-            except ValueError:
-                return None
-            except UserNotExists:
+                parsed_id = user_manager.parse_id(token)
+                return await user_manager.get(parsed_id)
+            except (InvalidID, UserNotExists):
                 return None
         return None
 
diff --git a/tests/test_authentication_authenticator.py b/tests/test_authentication_authenticator.py
index 7ad8c1bc..d2ee48e2 100644
--- a/tests/test_authentication_authenticator.py
+++ b/tests/test_authentication_authenticator.py
@@ -29,7 +29,7 @@ class MockTransport(Transport):
 
 class NoneStrategy(Strategy):
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         return None
 
@@ -39,7 +39,7 @@ class UserStrategy(Strategy, Generic[models.UP]):
         self.user = user
 
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         return self.user
 
diff --git a/tests/test_authentication_backend.py b/tests/test_authentication_backend.py
index 8aad2756..b7d99795 100644
--- a/tests/test_authentication_backend.py
+++ b/tests/test_authentication_backend.py
@@ -21,7 +21,7 @@ class MockTransportLogoutNotSupported(BearerTransport):
 
 class MockStrategyDestroyNotSupported(Strategy, Generic[models.UP]):
     async def read_token(
-        self, token: Optional[str], user_manager: BaseUserManager[models.UP]
+        self, token: Optional[str], user_manager: BaseUserManager[models.UP, models.ID]
     ) -> Optional[models.UP]:
         return None
 
diff --git a/tests/test_db_base.py b/tests/test_db_base.py
index 82501d2f..23e9e44b 100644
--- a/tests/test_db_base.py
+++ b/tests/test_db_base.py
@@ -3,7 +3,7 @@ import uuid
 import pytest
 
 from fastapi_users.db import BaseUserDatabase
-from tests.conftest import OAuthAccountModel, UserModel
+from tests.conftest import IDType, OAuthAccountModel, UserModel
 
 
 @pytest.mark.asyncio
@@ -11,7 +11,7 @@ from tests.conftest import OAuthAccountModel, UserModel
 async def test_not_implemented_methods(
     user: UserModel, oauth_account1: OAuthAccountModel
 ):
-    base_user_db = BaseUserDatabase[UserModel]()
+    base_user_db = BaseUserDatabase[UserModel, IDType]()
 
     with pytest.raises(NotImplementedError):
         await base_user_db.get(uuid.uuid4())
diff --git a/tests/test_fastapi_users.py b/tests/test_fastapi_users.py
index 8ca1af4d..ed929038 100644
--- a/tests/test_fastapi_users.py
+++ b/tests/test_fastapi_users.py
@@ -32,13 +32,14 @@ async def test_app_client(
     app.include_router(
         fastapi_users.get_oauth_router(oauth_client, mock_authentication, secret)
     )
-    app.include_router(fastapi_users.get_users_router(), prefix="/users")
-    app.include_router(fastapi_users.get_verify_router())
 
     @app.delete("/users/me")
     def custom_users_route():
         return None
 
+    app.include_router(fastapi_users.get_users_router(), prefix="/users")
+    app.include_router(fastapi_users.get_verify_router())
+
     @app.get("/current-user", response_model=User)
     def current_user(user: UserModel = Depends(fastapi_users.current_user())):
         return user
diff --git a/tests/test_manager.py b/tests/test_manager.py
index cc1360d9..6f423aab 100644
--- a/tests/test_manager.py
+++ b/tests/test_manager.py
@@ -1,5 +1,3 @@
-import copy
-import uuid
 from typing import Callable
 
 import pytest
@@ -18,7 +16,6 @@ from fastapi_users.manager import (
     UserNotExists,
 )
 from tests.conftest import (
-    OAuthAccountModel,
     UserCreate,
     UserManagerMock,
     UserModel,