Clerk Integration

Use Clerk for user sign-in, the kit's API keys for backend access.

Clerk handles user-facing authentication (sign-up, sign-in, session management, orgs). FastAPI AI Kit's JWT + API key system handles backend API access. Most teams run both: Clerk in front, kit-issued API keys behind it.

Setup in 4 steps

1Verify the Clerk session JWT on your frontend or a thin auth middleware
2On first authenticated request, issue a kit API key tied to the Clerk user ID
3Store the mapping between Clerk user ID and kit API key in your Postgres database
4Backend endpoints continue to use @require_api_key exactly as documented

What's included

No changes needed to the kit's existing require_api_key/rate_limit decorators
Clerk organizations map naturally onto per-team API key tiers
Stripe metering keeps working per API key, which you resolve back to a Clerk user
Avoids reimplementing session management or MFA inside the FastAPI service

Code example

example.py

# Backend: resolve Clerk user -> kit API key on first request
@router.post("/internal/session-exchange")
async def exchange_clerk_session(clerk_user_id: str, db: AsyncSession = Depends(get_db)):
    key = await get_or_create_api_key(db, external_id=clerk_user_id, provider="clerk")
    return {"api_key": key.raw_key}

# All existing endpoints work unchanged
@router.post("/v1/chat")
@require_api_key(tier=["basic", "pro"])
async def chat(...): ...

Full documentation: /docs/authentication

Clerk integration pre-wired and ready.

FastAPI AI Kit ships with Clerk configured out of the box. No manual setup required.

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