Rules are stored on the disk. Workers frequently pull rules from the disk and store them in the cache.

When a client sends a request to the server, the request is sent to the rate limiter middleware first.

Rate limiter middleware loads rules from the cache. It fetches counters and last request timestamp from Redis cache. Based on the response, the rate limiter decides:

if the request is not rate limited, it is forwarded to API servers.

if the request is rate limited, the rate limiter returns 429 too many requests error to the client. In the meantime, the request is either dropped or forwarded to the queue.