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API Gateway Monitoring

Links: 102 AWS DVA Index

Monitoring, Logging & Tracing

CloudWatch Logs

  • Enable CloudWatch logging at the Stage level (with Log Level)
  • Can override settings on a per API basis (ex: ERROR, DEBUG, INFO)
  • Log contains information about request/response body


  • Enable tracing to get extra information about requests in API Gateway
  • X-Ray API Gateway + AWS Lambda gives you the full picture

CloudWatch Metrics

  • Metrics are by stage, Possibility to enable detailed metrics
  • CacheHitCount & CacheMissCount: efficiency of the cache
  • Count: The total number API requests in a given period.
  • IntegrationLatency: The time between when API Gateway relays a request to the backend and when it receives a response from the backend.
  • Latency: The time between when API Gateway receives a request from a client and when it returns a response to the client.
    • The latency includes the integration latency and other API Gateway overhead.
    • Latency > IntegrationLatency
  • 4XXError (client-side) & 5XXError (server-side)
The maximum amount of time an API Gateway can perform any request is 29s so if Latency or IntegrationLatency is > 29s then we will see a timeout from API Gateway

API Throttling

  • Account Limit
    • API Gateway throttles requests at 10000 rps across all API. This means that if one of the APIs is under heavy use then other APIs can also be throttled.
    • Soft limit that can be increased upon request
  • In case of throttling => 429 Too Many Requests (retriable error). Client side error.
  • Can set Stage limit & Method limits to improve performance
  • Or you can define Usage Plans to throttle per customer
Just like Lambda Concurrency, if one API that is overloaded, if not limited, can cause the other APIs to be throttled


  • 4XX means Client errors
    • 400: Bad Request
    • 403: Access Denied, WAF filtered
    • 429: Quota exceeded, Throttle
  • 5XX means Server errors
    • 502: Bad Gateway Exception, usually for an incompatible output returned from a Lambda proxy integration backend and occasionally for out-of-order invocations due to heavy loads.
    • 503: Service Unavailable Exception. Backend is unavailable.
    • 504: Integration Failure.
      • Example: Endpoint Request Timed-out Exception
      • API Gateway requests time out after 29s maximum

Last updated: 2022-05-26