Stackure Python SDK

Passwordless magic-link authentication SDK for Python — drop-in ASGI and WSGI middleware, zero dependencies.

Protect an app with one line, or verify sessions and send magic links directly against the Stackure auth API.

Install

pip install stackure

Requires Python 3.14+.

Configure

export STACKURE_APP_SECRET=...   # from the app page in Stackure, shown once

Sent as X-App-Secret on every call. The first call that actually reaches Stackure raises StackureError("validation") if it is missing. STACKURE_BASE_URL optionally overrides the API host.

A newly registered app is not usable by anyone, even its creator, until it is shared with the organization or assigned to a team in Stackure. Do that before testing sign-in.

Protect an app

import stackure

app_id = "7f3c1a2e-9b4d-4e6f-8a1b-2c3d4e5f6071"  # your app's UUID in Stackure

# ASGI — FastAPI, Starlette, Quart
app = stackure.auth(app_id, "can_approve_invoice")(app)

# WSGI — Flask, Django
flask_app.wsgi_app = stackure.auth(app_id, "can_approve_invoice")(flask_app.wsgi_app)

The same wrapper handles both; it detects the protocol it was called under.

Access the authenticated user in your view:

user = stackure.user_from_request(request)
print(user.user_email, user.account_id, user.user_permissions)

• API requests get JSON errors
• Browser requests get redirected to sign-in
• The sign-in handoff is automatic: Stackure POSTs a session_token (an app-scoped session token valid only for this app) back to your app, the middleware validates it and stores it as a stackure_session cookie on your domain (not session, which Flask uses for its own session). Handoff bodies over 4 KB are ignored.

Requirements

Sessions are not bound to the browser's user agent or IP. The SDK still forwards the original User-Agent and X-Forwarded-For when validating from your server, but they are informational only.

Every request with a session token is validated against Stackure, so revocation is immediate. Requests without a well-formed token get the sign-in URL without a Stackure call.

Every call has one 2-second deadline covering connect, headers, body and the single retry. Calls retry once after 500 ms on a 5xx or a connection failure, never on a timeout. A timeout anywhere, including while reading the body, raises StackureError("timeout").

Verify manually

result = stackure.verify(app_id, request)

if not result.authenticated:
    # result.error.code, result.error.message, result.error.sign_in_url
    ...

# result.user

verify never raises — transport and API failures come back as a 500 result. It accepts a WSGI environ, an ASGI scope, or a framework request object (Starlette, FastAPI, Flask, Django).

Send a magic link

resp = stackure.send_magic_link("user@example.com", app_id)
# resp.message

Log out

r = stackure.logout(request)

Returns the status and headers that clear the app's cookie and redirect to Stackure's sign-out. Your framework builds the response:

# Flask
return "", r.status, r.headers

# Starlette / FastAPI
return Response(status_code=r.status, headers=dict(r.headers))

Errors

Everything except verify raises StackureError. Switch on .code:

from stackure import StackureError

try:
    stackure.send_magic_link(email)
except StackureError as err:
    match err.code:
        case "validation": ...  # bad input
        case "auth": ...        # 401 from the API
        case "forbidden": ...   # 403 from the API
        case "timeout": ...     # request exceeded the 2s deadline
        case "network": ...     # everything else

Contributing

Open a PR.

Security

Report vulnerabilities via GitHub Security Advisories. Releases publish to PyPI via OIDC trusted publishing with GitHub build-provenance attestations.

License

MIT