JWT Ninja

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

❤️ Contributions Welcome! Feel free to submit a PR.

Why JWT Ninja

• Stateful JWTs. Every token is tied to a DB-backed Session row — so you get token-based auth and revocation, device listing, and per-session state.
• Fully typed. Protected routes receive an AuthedRequest with request.auth.user and request.auth.session typed; OpenAPI schemas are generated with typed error responses.
• Flexible refresh-token transport. Use JSON body transport, HttpOnly cookies, or both.
• Batteries included. Five auth endpoints, a Django admin page, pluggable payload class for custom claims, pluggable authenticator for non-password login flows.

Upgrading

This release tightens several auth behaviours. Existing deployments should read these before upgrading:

• Refresh tokens no longer authenticate protected routes. JWTAuth now requires type == "access" and returns 401 invalid_token_type otherwise. If any client was sending its refresh token as a Bearer credential, it must switch to the access token.
• Refresh tokens are rotated on every use. /auth/refresh/ now returns a new refresh_token alongside the access token, and retires the one you sent. body-mode clients must persist and use the returned token; cookie-mode clients need no change. See Refresh token rotation.
• /auth/refresh/ now validates the session. A refresh token whose session was logged out or deleted is rejected instead of minting a new access token.
• Sessions now carry a hard expiry. JWT_SESSION_EXPIRE_SECONDS was previously ignored and sessions never aged out. It is now applied at session creation; set it to 0 to keep the old behaviour.
• expired_at is set on live sessions, so expired_at__isnull=True no longer means "active". Use Session.objects.active() in your own queries.
• Deleting a User now surfaces as session_not_found rather than invalid_user on /auth/refresh/, because the cascade removes the session first. Both 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.

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 wire up 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)

That's it — you now have /auth/login/, /auth/refresh/, /auth/sessions/, /auth/logout/, and /auth/logout/all/.

Protecting Your Views

Decorate any Ninja route with auth=JWTAuth() and annotate the request as AuthedRequest for 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 that you can use as scratch space for per-login state (feature flags, device info, onboarding step, etc.):

@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 refresh token is set as an HttpOnly cookie instead of being returned in JSON. In both mode, JWT Ninja does both.

POST /auth/refresh/

Request in body mode

{ "refresh_token": "eyJhbGci…" }

Request in cookie mode

Send the refresh token cookie previously set by /auth/login/.

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

All errors are returned as a JSON body {"error_code": "..."} with an appropriate HTTP status. Use these for i18n-friendly UX on the client.

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 and give attackers a smaller space to search — an attacker who recovers the key can forge arbitrary tokens for any user.

JWT Ninja emits jwt_ninja.settings.InsecureJWTKeyWarning at startup if your configured key is too short, so you'll see it 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 show up 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 (existing tokens fail signature verification), so users will need to re-authenticate after deploying 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 an appropriate SameSite policy for your application. SameSite="None" removes the browser's cross-site protection on the refresh endpoint — if you set it, add your own CSRF defence.

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.

Presenting a retired token is treated as evidence that the token leaked, and the whole session is revoked — the legitimate holder is logged out along with the attacker, which is the intended outcome once a token is known to be copied. The response is 401 token_reuse_detected.

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 token will log the user out. In cookie mode this is automatic — the server sets a replacement cookie each time.

The grace window

A client whose refresh response is lost to a dropped connection will retry with a token the server has already rotated past. To keep that from revoking real sessions, the immediately-previous token stays valid for JWT_REFRESH_TOKEN_REUSE_GRACE_SECONDS (default 30) after rotation.

Set it to 0 for strict single-use tokens, at the cost of logging 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. Such a token is honoured once, adopting the session into rotation, so upgrading doesn't log your whole userbase out. After that first use the old token is retired like any other.

Custom Claims

Need 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'll also need a custom authenticator (below) or a custom login endpoint that knows how to populate them.

Overriding user_id

If your User model uses a non-integer primary key (UUIDField, CharField, etc.), override user_id on your payload subclass so the declared type matches what user.id actually 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: user_id=user.id at the login site passes the PK 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 don't 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. Returning None produces a 401 invalid_credentials response.

Session Management

The Session model exposes a small set of helpers for common auth chores.

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 is a single bulk UPDATE that flips expired_at on every active session for the user.

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

Over time you'll accumulate rows for sessions that are long past their expired_at. Purge them with a scheduled task:

from jwt_ninja.models import Session

# django-crontab, Celery beat, management command, whatever you prefer
Session.purge_expired_sessions()

Inspect sessions in the admin

jwt_ninja registers a read-only SessionAdmin so ops can see who's logged in from where — just visit /admin/jwt_ninja/session/.

On the recorded IP address: Session.ip_address prefers the first entry in X-Forwarded-For and falls back to REMOTE_ADDR, and 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

Things JWT Ninja deliberately leaves to your application:

• Rate-limit /auth/login/. Nothing here throttles password guessing. Put a throttle in front of it — Django Ninja's built-in throttling, django-ratelimit, or your reverse proxy / WAF. Consider rate-limiting /auth/refresh/ too.
• Schedule Session.purge_expired_sessions(). Sessions now 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. Access tokens are checked against the DB session on every request, so revocation is quick — but 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.