I would add one suggestion/comment. Use a known set of standard error codes and not a unique error code/error type for each new situation. Error codes are the

I would add one suggestion/comment. Use a known set of standard error codes and not a unique error code/error type for each new situation. Error codes are there to hint to clients/callers what action they should potentially take (retry?, backoff) Don't make callers handle 100s of different potential error codes/types. If the whole internet can work with 70 your app can work with less. All of google uses less than 20 https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto https://github.com/googleapis/googleapis/blob/master/google/... Put more specific information in the error message or a secondary status code.