If a call exceeds the user or service rate limit for a given period of time, then subsequent calls made to limited endpoints will return a 429 "Rate limit exceeded" HTTP response until the rate limit expires.

In addition to the response code, some additional headers will be included in the response that provide more information.

Retry-After - The remaining number of seconds before the rate limit resets.

X-Rate-Limit-Type - The rate limit type, either "user" or "service".

If the above headers are not included in the response, then the rate limit was not enforced by the API infrastructure, but rather by the underlying service to which the request was proxied.