API gateway rate limiting

sequenceDiagram
    participant Client
    participant Gateway as API gateway
    participant Limiter as Rate limiter
    participant Service as Backend service

    Client->>Gateway: Request
    Gateway->>Limiter: Check quota
    alt Within limit
        Limiter-->>Gateway: Allowed
        Gateway->>Service: Forward request
        Service-->>Gateway: Response
        Gateway-->>Client: 200 OK
    else Over limit
        Limiter-->>Gateway: Denied
        Gateway-->>Client: 429 Too Many Requests
    end