GAE API quota limits

Question

I had been developing a GAE project that makes quite a number of logins and API calls for many Google Apps (Drive, spreadsheet, plus, groups, sites, etc). I was developing on a Google Apps for business domain with just 2 accounts and getting random errors very often. They mostly were 403 but also things like file not found when using Drive API; Of course other times the same exact things worked properly, so my guessing is this was related to API calls quota limit.
On occasions I kept getting that generic error saying 'something went wrong, that's all we know' for several minutes (up to 15-20 minutes).

I recently deployed the app to a Google Domain with over 100 accounts and all those errors seem to have vanished, which kinda confirm my guessing that they were indeed related to API calls quota limits, as the quota limit is said to be directly related to the number of accounts in the domain.

Is there any way where this quota and current usage can be checked? I can check many quotas under Google Cloud Console, but I can't find anything related to API usage.

Answer 1

What you observe might not be related to quota, the error is pretty explicit in that case, something like "QUOTA LIMIT EXCEEDED". I've been working with Google APIs for a long time now, and it's pretty common to get random issues like this. However, when you get a 404 from Drive it means that you don't have access to the file with the user you're using to make the API call. 403 would mean you are trying to perform a "writing" operation (update, patch) on a file with a user who has only reader access.

Anyway, to answer your question, you can now check the quota from the Developer Console under the APIs section of your project: