AuthKit

Authentication as a package for FastAPI. Install it, point it at a database and a secret key, and get email/password auth, JWT tokens, and Google sign-in — without writing any of it yourself.

from fastapi import FastAPI, Depends
from authkit import AuthKit

app = FastAPI()
auth = AuthKit(app, secret_key="...", database_url="postgresql+psycopg://...")
auth.include_routes()

@app.get("/dashboard")
async def dashboard(user=Depends(auth.login_required)):
    return {"user": user.email}

Nine routes, one dependency, zero boilerplate:

/auth/register              /auth/login               /auth/refresh
/auth/logout                /auth/me                  /auth/password-reset/request
/auth/password-reset/confirm                            /auth/email/verify/request
/auth/email/verify/confirm  /auth/google/login          /auth/google/callback

Table of contents

• Features
• Installation
• Quickstart
• Configuration reference
• API reference
• System design
• Data model
• Roadmap
• Development
• Contributing
• License

Features

• Email + password auth — register, login, is_active gating
• JWT access + refresh tokens — short-lived access token, longer-lived refresh token, independent expiry configuration
• login_required dependency — one Depends() call protects any route and injects the current user
• Logout / token revocation — an in-memory blacklist so a logged-out token can't be reused
• Google sign-in (OAuth 2.0) — full authorization-code flow, CSRF-protected state, account linking so a user can have both a password login and a Google login on the same account
• Password reset — request/confirm flow with single-use, hashed, expiring tokens
• Email verification — same token mechanism, separate purpose
• Rate limiting — per-IP sliding window on /login and /register
• Pluggable side effects — AuthKit never sends an email or decides how to redirect after OAuth; you supply the hook, AuthKit calls it
• Bring your own database — any SQLAlchemy-supported engine; tables are namespaced (authkit_*) so they never collide with your app's own schema

Installation

PyPI publication is pending. Until then, install directly from GitHub:

pip install git+https://github.com/<your-username>/authkit.git

Pin to a tag once you have one (recommended for anything beyond local experimentation):

pip install git+https://github.com/<your-username>/authkit.git@v0.1.0

With Poetry, as a git dependency in pyproject.toml:

authkit = { git = "https://github.com/<your-username>/authkit.git", tag = "v0.1.0" }

Once published to PyPI, installation will be:

pip install fastapi-authstack

Quickstart

from fastapi import FastAPI, Depends
from authkit import AuthKit

app = FastAPI()

auth = AuthKit(
    app,
    secret_key="change-me-to-a-real-secret",
    database_url="sqlite:///./app.db",
)
auth.include_routes()

@app.get("/dashboard")
async def dashboard(user=Depends(auth.login_required)):
    return {"email": user.email, "verified": user.email_verified}

uvicorn main:app --reload

curl -X POST localhost:8000/auth/register \
  -H "Content-Type: application/json" \
  -d '{"email": "you@example.com", "password": "supersecret123"}'

curl -X POST localhost:8000/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email": "you@example.com", "password": "supersecret123"}'

curl localhost:8000/dashboard \
  -H "Authorization: Bearer <access_token from login response>"

Configuration reference

auth = AuthKit(
    app,
    secret_key="...",                     # required — used to sign JWTs and OAuth state
    database_url="postgresql+psycopg://user:pass@host/db",
    algorithm="HS256",
    access_token_expires_minutes=15,
    refresh_token_expires_days=7,
    action_token_expires_minutes=30,      # password reset / email verification token TTL
    auto_create_tables=True,              # False if you manage migrations yourself
    engine_options=None,                  # forwarded to sqlalchemy.create_engine
    google_oauth={
        "client_id": "...",
        "client_secret": "...",
        "redirect_uri": "https://yourapp.com/auth/google/callback",
    },
    on_password_reset_requested=lambda user, token: send_email(user, token),
    on_email_verification_requested=lambda user, token: send_email(user, token),
    on_oauth_login_complete=lambda user, tokens, redirect_after: my_redirect(user, tokens, redirect_after),
)

Parameter	Required	Default	Notes
secret_key	✅	—	Signs JWTs and OAuth state tokens
database_url	✅	—	Any SQLAlchemy-compatible URL
google_oauth	—	None	Omit entirely to disable Google sign-in — its routes won't be mounted
auto_create_tables	—	True	Set False and run your own migration if you use Alembic
on_password_reset_requested	—	no-op	(user, raw_token) -> None — send the email yourself
on_email_verification_requested	—	no-op	Same shape as above
on_oauth_login_complete	—	redirect with base64 payload	(user, tokens, redirect_after) -> Response

API reference

Method	Path	Auth required	Description
POST	/auth/register	No	Create an account, returns user + token pair
POST	/auth/login	No	Authenticate, returns user + token pair
POST	/auth/refresh	No (refresh token)	Exchange a refresh token for a new pair
POST	/auth/logout	Yes	Revoke the current access token
GET	/auth/me	Yes	Return the current user
POST	/auth/password-reset/request	No	Issue a password reset token via the configured hook
POST	/auth/password-reset/confirm	No (reset token)	Consume the token, set a new password
POST	/auth/email/verify/request	Yes	Issue an email verification token via the configured hook
POST	/auth/email/verify/confirm	No (verification token)	Consume the token, mark the email verified
GET	/auth/google/login	No	Redirect to Google's consent screen
GET	/auth/google/callback	No	Handle Google's callback, create/link the user, redirect

All error responses are {"detail": "..."} with the appropriate HTTP status — 401 for bad credentials/tokens, 403 for inactive accounts, 409 for duplicate registration, 429 for rate limiting.

System design

AuthKit is a single facade (AuthKit) composing four independent layers. Each layer only depends on the layers below it — there are no upward or circular imports, which keeps every piece independently testable and replaceable.

                      ┌───────────────────────────────────────────┐
                      │                AuthKit (core.py)            │
                      │   the only class an integrator touches       │
                      └───────────────────┬───────────────────────┘
                                          │ wires together
        ┌─────────────────────┬─────────┼─────────────────┬─────────────────────┐
        ▼                     ▼                             ▼                     ▼
┌───────────────┐   ┌──────────────────┐        ┌──────────────────┐   ┌──────────────────┐
│    routes/      │   │    services/       │        │      oauth/        │   │  dependencies.py  │
│  HTTP contracts  │──▶│  business logic    │        │  provider adapters  │   │  FastAPI Depends()  │
│  auth.py         │   │  AuthService        │        │  base / google /    │   │  login_required     │
│  google.py       │   │  TokenService       │        │  state / redirect   │   │  get_session         │
└───────────────┘   │  ActionTokenService │        └──────────────────┘   └──────────────────┘
                      └─────────┬──────────┘
                                │ reads/writes through
                                ▼
                      ┌──────────────────┐
                      │  repositories/      │
                      │  UserRepository     │   ← the only layer that writes SQL
                      └─────────┬──────────┘
                                ▼
                      ┌──────────────────┐
                      │     models.py        │   User · UserIdentity · ActionToken
                      └─────────┬──────────┘
                                ▼
                      ┌──────────────────┐
                      │      db.py            │   SQLAlchemy engine + session factory
                      └──────────────────┘

  cross-cutting, used by routes/services directly:
  config.py (typed settings) · security.py (hashing + JWT primitives)
  exceptions.py (typed errors → HTTP status) · rate_limit.py · token_blacklist.py

Why layered this way:

• Routes never touch the database. They validate input, call a service, and shape the HTTP response. All persistence goes through repositories/.
• Services own business rules, not SQL or HTTP. AuthService.authenticate doesn't know it's being called from a FastAPI route — it just raises a typed exception on failure.
• One exception hierarchy (AuthKitError) maps to HTTP status codes in one place — a single @app.exception_handler(AuthKitError) registered in core.py. No route handler contains a raw HTTPException.
• OAuth providers implement one interface (oauth/base.py: OAuthProvider). Google is the only implementation today; adding GitHub or Microsoft is a new file in oauth/, not a change to core.py or the route layer.
• Every side effect the host application needs to control is a hook, not a hardcoded integration. AuthKit does not send emails or decide how to redirect after OAuth login — it calls on_password_reset_requested, on_email_verification_requested, and on_oauth_login_complete, which the integrator supplies. AuthKit's job is auth, not email delivery.

Data model

• User — one row per account. hashed_password is nullable, because an OAuth-only user has no password.
• UserIdentity — links a User to a third-party provider (provider, provider_user_id). A user can have a password login and a Google login on the same account, matching how real products behave.
• ActionToken — single-use, hashed, expiring tokens for password reset and email verification, keyed by purpose.

Tables are prefixed authkit_* so they never collide with the host application's own schema.

Roadmap

Deliberately out of scope for v1, planned as the next layer on top of this one:

• Two-factor authentication (TOTP)
• API keys (create, scope, rotate, revoke)
• Roles & permissions
• Multi-tenant organizations (teams, invitations, membership)
• Additional OAuth providers (GitHub, Microsoft)
• Persistent token blacklist (Redis-backed, for multi-process deployments)

Development

Requires Python 3.11+.

git clone https://github.com/<your-username>/authkit.git
cd authkit
python3 -m venv venv && source venv/bin/activate
pip install -e .
pip install pytest
pytest

The test suite runs against an in-memory SQLite database — no external services required.

Contributing

Issues and pull requests are welcome. Before opening a PR:

1. Run pytest and make sure everything passes
2. Keep the layering intact — routes call services, services call repositories, nothing skips a layer
3. Match the existing style: no comments, self-explanatory names, typed function signatures

License

MIT — see LICENSE.