Why Is Status Code 429 Returned When I Call the ServiceComb Engine API?

Symptom

When an API is called, the server returns HTTP status code 429 "Too Many Requests".

Possible Cause

Status code 429 indicates that the number of requests sent by the client in a unit time exceeds the threshold set on the server, triggering rate limiting protection. This is a common measure taken by the server to ensure system stability and prevent resource abuse.

Trigger Conditions

• An API is frequently called within a short period (for example, the QPS exceeds the upper limit).
• The request sending frequency is out of the allowed range.

Solution

• Check the rate limiting rules of the API (such as the maximum number of requests per second or per minute and the quota period) and ensure that the request sending frequency is within the allowed range.
• After status code 429 is returned, perform retries based on the exponential backoff strategy to gradually increase the retry interval. For example, wait for 1 second for the first retry and double the waiting time for the next retry.