JWT Ninja

A session-backed, fully-typed authentication library for Django Ninja, powered by PyJWT.

Contributions are welcome. Submit a PR.

Why JWT Ninja

• Stateful JWTs. Every token maps to a Session row in the database. You get token-based auth plus revocation, device listing, and per-session state.
• Fully typed. Protected routes receive an AuthedRequest with typed request.auth.user and request.auth.session. OpenAPI schemas include typed error responses.
• Three refresh-token transports. JSON body, HttpOnly cookie, or both.
• Complete. Five auth endpoints, a Django admin page, a pluggable payload class for custom claims, and a pluggable authenticator for non-password login flows.

Table of Contents

• Install
• Quick start
• Protecting your views
• Endpoints
• Error codes
• Upgrading
• Configuration
• Signing key length
• Refresh token transport
• Refresh token rotation
• Custom claims
• Custom authenticator
• Session management
• Deployment checklist
• Development

Install

JWT Ninja is a standard Django app. Install it with uv or pip:

uv add jwtninja
# or
pip install jwtninja

Requires Python 3.12+ and Django 5.x.

Asymmetric signing algorithms (RS*, ES*, PS*, EdDSA) need PyJWT's cryptography extra:

uv add "jwtninja[crypto]"
# or
pip install "jwtninja[crypto]"

Quick start

1. Add jwt_ninja to your INSTALLED_APPS:

# settings.py
INSTALLED_APPS = [
    ...,
    "jwt_ninja",
]

2. Run migrations to create the Session table:

python manage.py migrate

3. Mount the router on your Ninja API and register the error handler:

from ninja import NinjaAPI
from jwt_ninja import APIError
from jwt_ninja.api import router as auth_router
from jwt_ninja.handlers import error_handler

api = NinjaAPI()
api.add_router("auth/", auth_router)
api.add_exception_handler(APIError, error_handler)

This gives you /auth/login/, /auth/refresh/, /auth/sessions/, /auth/logout/, and /auth/logout/all/.

Protecting your views

Add auth=JWTAuth() to any Ninja route. Annotate the request as AuthedRequest to get typed access to the authenticated user and session:

from ninja import Router
from jwt_ninja import AuthedRequest, JWTAuth

router = Router()


@router.get("/profile/", auth=JWTAuth())
def profile(request: AuthedRequest):
    user = request.auth.user  # the Django User
    session = request.auth.session  # the jwt_ninja Session
    return {"username": user.username, "session_id": session.id}

Per-session state

Each Session has a JSONField called data. Use it to store per-login state such as feature flags, device info, or an onboarding step:

@router.post("/set-theme/", auth=JWTAuth())
def set_theme(request: AuthedRequest, theme: str):
    request.auth.session.data["theme"] = theme
    request.auth.session.save()
    return {"ok": True}

Endpoints

POST /auth/login/

Request

{ "username": "alice", "password": "hunter2" }

Response (200) in body mode

{ "access_token": "eyJhbGci…", "refresh_token": "eyJhbGci…" }

Response (200) in cookie mode

{ "access_token": "eyJhbGci…" }

In cookie mode, the server sets the refresh token as an HttpOnly cookie and does not return it in JSON. In both mode, it does both.

POST /auth/refresh/

Request in body mode

{ "refresh_token": "eyJhbGci…" }

Request in cookie mode

Send the refresh token cookie that /auth/login/ set.

Response (200) in body mode

{ "access_token": "eyJhbGci…", "refresh_token": "eyJhbGci…" }

Response (200) in cookie mode

{ "access_token": "eyJhbGci…" }

Refresh tokens are rotated. Every call to /auth/refresh/ returns a new refresh token and retires the one you sent. Store the new token and use it for the next refresh. See Refresh token rotation.

Error codes

Every error returns a JSON body {"error_code": "..."} with a matching HTTP status. Use the codes to build client-side messages and translations.

Upgrading

This release tightens several auth behaviors. Read these notes before you upgrade an existing deployment:

• Refresh tokens no longer authenticate protected routes. JWTAuth now requires type == "access". Any other token type gets 401 invalid_token_type. If a client sends its refresh token as a Bearer credential, it must switch to the access token.
• Refresh tokens rotate on every use. /auth/refresh/ now returns a new refresh_token with the access token and retires the one you sent. Clients in body mode must store and use the returned token. Clients in cookie mode need no change. See Refresh token rotation.
• /auth/refresh/ now validates the session. If the session was logged out or deleted, the server rejects the refresh token instead of minting a new access token.
• Sessions now have a hard expiry. Earlier versions ignored JWT_SESSION_EXPIRE_SECONDS, so sessions never expired. The setting now applies at session creation. Set it to 0 to keep the old behavior.
• expired_at is set on live sessions. expired_at__isnull=True no longer means "active". Use Session.objects.active() in your own queries.
• Deleting a User now returns session_not_found on /auth/refresh/, not invalid_user. The delete cascade removes the session first. Both codes are 401.
• JWT_ALGORITHM is validated at startup. none, typos, and asymmetric algorithms without the crypto extra now raise ImproperlyConfigured instead of failing later.

Run python manage.py migrate to add the rotation columns.

Configuration

All settings are Django settings prefixed with JWT_. Defaults shown below:

# settings.py
JWT_SECRET_KEY = SECRET_KEY  # Defaults to Django's SECRET_KEY
JWT_ALGORITHM = "HS256"
JWT_ACCESS_TOKEN_EXPIRE_SECONDS = 300  # 5 minutes
JWT_REFRESH_TOKEN_EXPIRE_SECONDS = 365 * 3600  # ~15 days
JWT_SESSION_EXPIRE_SECONDS = 365 * 3600  # ~15 days (0 disables session expiry)
JWT_REFRESH_TOKEN_REUSE_GRACE_SECONDS = 30  # 0 disables the grace window
JWT_USER_LOGIN_AUTHENTICATOR = "jwt_ninja.authenticators.django_user_authenticator"
JWT_PAYLOAD_CLASS = "jwt_ninja.types.JWTPayload"
JWT_REFRESH_TOKEN_TRANSPORT = "body"  # "body", "cookie", or "both"
JWT_REFRESH_COOKIE_NAME = "refresh_token"
JWT_REFRESH_COOKIE_SECURE = True
JWT_REFRESH_COOKIE_HTTPONLY = True
JWT_REFRESH_COOKIE_SAMESITE = "Lax"  # "Lax", "Strict", or "None"
JWT_REFRESH_COOKIE_PATH = "/auth/refresh/"
JWT_REFRESH_COOKIE_DOMAIN = None

Signing key length

For HMAC algorithms (the HS* family, including the default HS256), RFC 7518 §3.2 requires the signing key to be at least the size of the hash output:

Shorter keys are padded internally, which gives an attacker a smaller space to search. An attacker who recovers the key can forge tokens for any user.

JWT Ninja emits jwt_ninja.settings.InsecureJWTKeyWarning at startup if your configured key is too short. The warning appears in your app logs as soon as the settings load. PyJWT also emits its own InsecureKeyLengthWarning at encode/decode time.

Django's get_random_secret_key() already produces 50-character keys, so fresh projects are fine. Short keys typically appear in older projects or in manually set JWT_SECRET_KEY values. To generate a suitable key:

python -c "from django.core.management.utils import get_random_secret_key; print(get_random_secret_key())"

Rotating the key invalidates all existing JWT Ninja sessions, because existing tokens fail signature verification. All users must log in again after you deploy the change.

Refresh token transport

JWT Ninja supports three refresh-token transport modes:

• "body" (default) — login/ returns refresh_token in JSON, and refresh/ expects it in the request body.
• "cookie" — login/ sets the refresh token in an HttpOnly cookie, and refresh/ reads it from that cookie.
• "both" — login/ returns the refresh token in JSON and sets the cookie. refresh/ accepts either the request body or the cookie.

Example browser-oriented configuration:

JWT_REFRESH_TOKEN_TRANSPORT = "cookie"
JWT_REFRESH_COOKIE_SECURE = True
JWT_REFRESH_COOKIE_HTTPONLY = True
JWT_REFRESH_COOKIE_SAMESITE = "Lax"
JWT_REFRESH_COOKIE_PATH = "/auth/refresh/"

In cookie mode:

• POST /auth/login/ returns the access_token in JSON and sets the refresh token cookie.
• POST /auth/refresh/ reads the refresh token from the cookie.
• POST /auth/logout/ and POST /auth/logout/all/ clear the refresh token cookie.

Security note: HttpOnly cookies reduce refresh-token exposure to JavaScript, but cookie-based auth flows are still subject to CSRF considerations. For browser deployments, prefer Secure=True, keep refresh endpoints as POST, and choose a SameSite policy that fits your application. SameSite="None" removes the browser's cross-site protection on the refresh endpoint. If you set it, add your own CSRF defense.

Refresh token rotation

Every call to /auth/refresh/ mints a new refresh token and retires the one you presented. Each refresh token carries a jti claim, and the session row records the only jti it currently accepts.

The server treats a retired token as evidence that the token leaked, and revokes the whole session. The response is 401 token_reuse_detected. This logs out the legitimate holder along with the attacker, which is the intended outcome once a token is known to be copied.

What clients must do: in body mode, persist the refresh_token from every /auth/refresh/ response and send that one next time. Replaying a stored old token will log the user out. In cookie mode this is automatic, because the server sets a replacement cookie each time.

The grace window

A dropped connection can lose the refresh response. The client then retries with a token the server has already rotated past. To keep that retry from revoking a real session, the previous token stays valid for JWT_REFRESH_TOKEN_REUSE_GRACE_SECONDS (default 30) after rotation.

Set it to 0 for strict single-use tokens. That choice logs out users whose refresh request gets retried.

Upgrading existing deployments

Refresh tokens issued before rotation existed carry no jti, and their sessions have no recorded jti either. The server accepts such a token once and adopts the session into rotation, so upgrading does not log out your whole user base. After that first use, the old token is retired like any other.

Custom claims

To embed extra data in the token itself (team id, feature flags, etc.), subclass JWTPayload and point JWT_PAYLOAD_CLASS at it. Encode and decode sites both use the configured class, so your custom fields round-trip end to end.

# myapp/auth.py
from jwt_ninja import JWTPayload


class CustomJWTPayload(JWTPayload):
    team_id: int
    email: str

# settings.py
JWT_PAYLOAD_CLASS = "myapp.auth.CustomJWTPayload"

Note: If you add required fields, you also need a custom authenticator (below) or a custom login endpoint that populates them.

Overriding user_id

If your User model uses a non-integer primary key (UUIDField, CharField, etc.), override user_id on your payload subclass. The declared type must match what user.id is at runtime:

from uuid import UUID
from jwt_ninja import JWTPayload


class UUIDJWTPayload(JWTPayload):
    user_id: UUID  # or str, depending on your User PK


class StrPKJWTPayload(JWTPayload):
    user_id: str

Pydantic is strict about this. The login site passes user.id through without coercion, so the declared type and the runtime type must agree. The default JWTPayload declares user_id: int, which matches Django's default AutoField primary key.

Custom authenticator

If you do not use Django's username/password flow (SSO, magic links, OTP, etc.), point JWT_USER_LOGIN_AUTHENTICATOR at a callable that returns a User or None:

# myapp/auth.py
from django.contrib.auth import get_user_model
from django.http import HttpRequest
from django.utils.timezone import now

User = get_user_model()


def magic_link_authenticator(request: HttpRequest, payload) -> User | None:
    try:
        return User.objects.get(magic_token=payload.token, magic_token_expired_at__gt=now())
    except User.DoesNotExist:
        return None

# settings.py
JWT_USER_LOGIN_AUTHENTICATOR = "myapp.auth.magic_link_authenticator"

The callable receives the raw HttpRequest and the parsed LoginSchema payload. If it returns None, the response is 401 invalid_credentials.

Session management

The Session model has helpers for common auth tasks.

Invalidate all sessions (e.g., on password change)

from jwt_ninja.models import Session

# On password change, log the user out of every device
Session.invalidate_all_user_sessions(user)

This runs one bulk UPDATE that sets expired_at on every active session for the user.

Purge expired sessions (e.g., nightly cron)

Over time, rows accumulate for sessions long past their expired_at. Delete them with a scheduled task:

from jwt_ninja.models import Session

# Run from django-crontab, Celery beat, or a management command
Session.purge_expired_sessions()

Inspect sessions in the admin

jwt_ninja registers a read-only SessionAdmin at /admin/jwt_ninja/session/. Use it to see which users are logged in, and from where.

On the recorded IP address: Session.ip_address prefers the first entry in X-Forwarded-For and falls back to REMOTE_ADDR. Non-IP values are discarded rather than stored. Any client can send X-Forwarded-For, so the value is only trustworthy if a proxy you control overwrites the header on the way in. Treat it as a hint for support and debugging, not as evidence in an investigation.

Deployment checklist

JWT Ninja deliberately leaves these tasks to your application:

• Rate-limit /auth/login/. Nothing in JWT Ninja throttles password guessing. Put a throttle in front of the endpoint: Django Ninja's built-in throttling, django-ratelimit, or your reverse proxy or WAF. Consider a rate limit on /auth/refresh/ too.
• Schedule Session.purge_expired_sessions(). Sessions carry a hard expiry, but nothing deletes the rows until you run the purge. See Purge expired sessions.
• Serve over HTTPS. Access tokens are bearer credentials. Anyone who observes one can use it until it expires.
• Keep JWT_ACCESS_TOKEN_EXPIRE_SECONDS short. Every request checks the access token against the DB session, so revocation is quick. A short lifetime is still your backstop.
• Set a strong signing key. See Signing key length.

Development

# Clone and install
git clone https://github.com/dvf/jwt-ninja
cd jwt-ninja
uv sync

# Run tests
uv run pytest

# Lint + format
uv run ruff check .
uv run ruff format .

# Static type check
uv run pyrefly check

PRs are gated on all four checks. See .github/workflows/check-and-test.yml.

License

MIT — see LICENSE.