Usage limits

Because the Google Chat API is a shared service, we apply quotas and limitations to make sure that it's used fairly by all users and to protect the overall performance of Google Workspace.

If you exceed a quota, you'll receive a 429: Too many requests HTTP status code response. Additional rate limit checks on the Chat backend might also generate the same error response. If this error happens, you should use an exponential backoff algorithm and try again later. As long as you stay within the per-minute quotas listed in the following table, there's no limit to the number of requests you can make per day.

There are 10 quota categories in total that are applicable to various Chat API methods. Each category has its own rate limit.

The following table details the query limits:


Chat API methods

Limit (per 60 seconds)

Message writes per minute





Message reads per minute




Membership writes per minute




Membership reads per minute




Space writes per minute






Space reads per minute





Attachment writes per minute



Attachment reads per minute



Reaction writes per minute




Reaction reads per minute



Additional usage limits

There might be additional quota limits for creating spaces of type GROUP_CHAT or SPACE (by using either the spaces.create or the spaces.setup method). Create less than 10 spaces per minute and 60 spaces per hour of these types. Spaces of type DIRECT_MESSAGE aren't subject to these additional quota limits.

Large queries per second (QPS) of any API targeting the same space can trigger additional internal limits that aren't visible in the Quotas page.

Resolve time-based quota errors

For all time-based errors (maximum of N requests per X minutes), we recommend your code catches the exception and uses a truncated exponential backoff to make sure your devices don't generate excessive load.

Exponential backoff is a standard error handling strategy for network applications. An exponential backoff algorithm retries requests using exponentially increasing wait times between requests, up to a maximum backoff time. If requests are still unsuccessful, it's important that the delays between requests increase over time until the request is successful.

Example algorithm

An exponential backoff algorithm retries requests exponentially, increasing the wait time between retries up to a maximum backoff time. For example:

  1. Make a request to Google Chat API.
  2. If the request fails, wait 1 + random_number_milliseconds and retry the request.
  3. If the request fails, wait 2 + random_number_milliseconds and retry the request.
  4. If the request fails, wait 4 + random_number_milliseconds and retry the request.
  5. And so on, up to a maximum_backoff time.
  6. Continue waiting and retrying up to some maximum number of retries, but don't increase the wait period between retries.


  • The wait time is min(((2^n)+random_number_milliseconds), maximum_backoff), with n incremented by 1 for each iteration (request).
  • random_number_milliseconds is a random number of milliseconds less than or equal to 1,000. This helps to avoid cases in which many clients are synchronized by some situation and all retry at once, sending requests in synchronized waves. The value of random_number_milliseconds is recalculated after each retry request.
  • maximum_backoff is typically 32 or 64 seconds. The appropriate value depends on the use case.

The client can continue retrying after it has reached the maximum_backoff time. Retries after this point don't need to continue increasing backoff time. For example, if a client uses a maximum_backoff time of 64 seconds, then after reaching this value, the client can retry every 64 seconds. At some point, clients should be prevented from retrying indefinitely.

The wait time between retries and the number of retries depend on your use case and network conditions.

Request a quota increase

Depending on your project's resource usage, you might want to request a quota increase. API calls by a service account are considered to be using a single account. Applying for an increased quota doesn't guarantee approval. Large quota increases can take longer to be approved.

Not all projects have the same quotas. As you increasingly use Google Cloud over time, your quotas might need to increase. If you expect a notable upcoming increase in usage, you can proactively request quota adjustments from the Quotas page in the Google Cloud console.

To learn more, see the following resources: