How to set rate limit and burst in a usage plan in api gateway?

This is related to the token bucket algorithm.

Firstly from the definition [1]: A burst limit represents the maximum number of concurrent requests at any given time, while a rate limit defines the number of requests allowed per second.

Allow me to refer to the below image from [2], and assume x-axis represents 100 ms while y-axis represents the number of requests.

In this case, our back-end is designed to handle 30 RPS workload, with the capability to process at most 12 (spiky) requests. Therefore, I would set the rate limit to 30 and the burst limit to 12 accordingly.

Both limits protect my backend from being overloaded.

[1] https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-request-throttling.html

[2] https://www.geeksforgeeks.org/leaky-bucket-algorithm/