Definition
JSON Web Tokens (JWT) are a compact, URL-safe method for representing claims between two parties. In API authentication, a JWT is issued at login and included in subsequent requests. The server validates the token's signature without a database lookup, making it stateless and horizontally scalable.
Why it matters for AI APIs
JWT authentication is the standard for modern API security. It decouples auth from your database, supports microservices, and integrates with API key systems. Every SaaS API and AI product needs both user-level JWTs and API key issuance for programmatic access.
In FastAPI AI Kit
FastAPI AI Kit ships a complete JWT + API key system: user registration, JWT issuance with configurable expiry, API key creation and rotation, per-key metadata (owner, tier, limits), and `@require_api_key` decorator for route protection. No additional libraries needed.