How strict is the Gmail API's per user per second quota?

Question

Google's documentation states that there is a 25 quota unit rate limit per user per second:

https://developers.google.com/gmail/api/v1/reference/quota

My use case for the Gmail API requires downloading a user's entire mailbox and it appears that use case may not be feasible given these quotas. Downloading 10,000 messages would take roughly 33 minutes.

However, that link also states that the limit is a moving average and suggests that it can be exceeded in small bursts. Can that limit be exceeded significantly enough to meet my use case?

Answer 1

You can raise the per-user limit to 50 units/user/second for your project in the developers console. The limit is only applied over a longer moving window, so you can definitely exceed it for a little bit (O(seconds)). If you need more for longer period, you can request more quota.

Answer 2

While not a full answer, here is my experience on migrating from Gmail to Google Apps for work. My 120000+ conversations/ 200000+ messages mailbox ran close to the 15 GB limit, so I decided to professionalize my account.

After almost 2 days I am now at 22 percent of that migration both in terms of numbers as well as Gigabytes. That is about 60 megabytes/hour and 1000 messages/hour.

Fortunately this runs in reverse chronological order.