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The complete backend for API-first SaaS products.

JWT auth, API key management, Stripe usage metering, rate limiting, and background jobs — the entire infrastructure layer for a SaaS API, pre-built and production-ready.

FastAPISQLAlchemyPostgreSQLStripeRedisCelery

The usual pain points

✕Building JWT auth and API key systems from scratch
✕Implementing usage-based billing that tracks actual consumption
✕Per-customer rate limiting across API keys
✕Background jobs for async processing without managing workers

How the kit solves them

Complete JWT + API key system on day one — issuance, rotation, revocation
Stripe usage metering hooks wired to per-request token/event counting
Per-key rate limiting with per-minute and per-day configurable limits
Celery + Redis or arq for background job processing, pre-configured

Example implementation

main.py

# Usage-metered endpoint — everything pre-wired
@router.post("/v1/process")
@require_api_key(tier=["basic", "pro"])
@rate_limit(per_minute=60, per_day=10_000)
async def process_request(
    body: ProcessRequest,
    key: APIKey = Depends(get_api_key),
):
    result = await processor.run(body.input)
    # Automatically meters usage to Stripe
    await meter.record(key.id, units=result.units)
    return ProcessResponse(output=result.data)

Ready to build your saas api backend?

FastAPI AI Kit ships with everything shown above, pre-configured and production-ready. Clone the repo and start building in minutes.

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