I’m working on an application that needs to connect to Gmail accounts through their API. The app will handle email operations like sending messages after users give permission to access their Gmail data.
My main question is about how Google calculates the API limits. Are the quotas applied per application or per individual user account?
Let me explain my concern with a scenario. Say my application has 500,000 active users and Google sets a daily limit of 50,000 requests. Does this mean:
Option A: My entire app gets blocked after 50,000 total requests from all users combined?
Option B: Each individual user account can make up to 50,000 requests independently?
I’m worried that if it’s Option A, my app will stop working once we hit the combined limit across all users. This would make the Gmail API unusable for larger applications.
I found some documentation that mentions rate limiting as “one request per second per user” but it doesn’t clarify what “user” means in this context. Is it the Gmail account holder, the IP address making the request, or something else?
If the limits work like Option A, I might need to stick with traditional SMTP/POP3 connections instead of using the Gmail API. Any insights on how these quotas actually work would be really helpful.
yeah, can confirm it’s per-user quotas, not total app limits. i’ve been running Gmail API for 2+ years with 200k+ users and never hit any combined limits. each Gmail account gets its own allowance, so you don’t need to worry about option A. just handle 429 responses properly when users hit their individual limits.
Based on my experience with the Gmail API, you can rest assured that the limits are applied per individual user account, which corresponds to Option B. Each user maintains their own quota, meaning that if one user exceeds their limit, it won’t affect others using your application. The reference to ‘one request per second per user’ indeed refers to the Gmail account holder. With a user base of 500,000, you’ll have a significant number of individual limits to work with. While there are project-level quotas to consider, they generally come into play only under heavier usage, and you can adjust these in the Google Cloud Console as necessary. The key challenge lies in managing rate limit responses, so implementing exponential backoff will be critical as you scale.
It’s Option B - quotas work per user. I’ve built several Gmail API integrations over the years, and Google scales with your user base instead of throttling it. Each Gmail account gets its own quota separately, so your 500k users could theoretically hit 25 billion requests daily (assuming the standard 50k limit each). The docs can be confusing here, but ‘user’ means the Gmail account owner who gave your app OAuth permissions. There are project-level quotas in Google Cloud Console, but they’re usually way higher and you can request increases if needed. Your real bottleneck will be rate limits per individual user, not aggregate limits. Focus your error handling on managing individual user timeouts and solid retry logic.