title: Throttling between API Gateway and Lambda
body: <p>From my understanding, API Gateway by default has a 1000 RPS limit--when this is crossed, it will begin throttling calls and returning 429 error codes. Past the Gateway, Lambda has a 100 concurrent invocation limit, and when this is crossed, it will begin throttling calls and returning 500 (or 502) error codes. </p>
  
  <p>Given that, when viewing my graph on Cloudwatch, I would expect my number of throttled calls to be closer to the number of 4XX errors, or at least above the number of 5XX errors, because the calls must pass through API Gateway first in order to get to Lambda at all. However, it looks like the number of throttled calls is closer to the number of 5XX errors. </p>
  
  <p>Is there something I might be missing from the way I'm reading the graph? </p>