Where or in which component of the system can a request rate limiting mechanism be implemented?

The mechanism of rate limiting is usually implemented at:

• Web servers (e.g., nginx) — to filter traffic before it reaches the application.
• Middleware layer within the application — intercepting requests and controlling their frequency.
• API Gateway — if a microservices architecture is used.

In Go, rate limiting can be implemented using token buckets or counters in middleware to limit the number of requests from a single user or IP over a specified period.