Rate limits in Nylas

Rate limits apply when making requests to the Nylas API and adding account information in the Dashboard. This page describes the limits you may encounter.

For best practices to mitigate rate limits, see Avoiding rate limits in Nylas.

Nylas rate limits

The table below describes API rate limits for Nylas v3. These apply to all endpoints.

API	Type	Rate Limit	Expiration
Applications	General	Allows up to 50 requests per application.	1 second
Authentication	General	Allows up to 50 requests per application.	1 second
Calendar	General	Allows up to 200 requests per grant.	1 second
Connectors	General	Allows up to 50 requests per application.	1 second
Contacts	General	Allows up to 200 requests per grant.	1 second
Email	General	Allows up to 200 requests per grant.	1 second
Grants	General	Allows up to 50 requests per application.	1 second
Send	application/json	Allows up to 200 requests per grant.	1 second
Send	multipart/form-data	Allows up to 10 requests per grant.	1 second
Webhooks	General	Allows up to 50 requests per application.	1 second

Threads rate limits

The Return all Threads endpoint makes a significant number of calls to the provider for each request you make. Because of this, Nylas strongly recommends using query parameters to limit the threads data you receive.

Because of the number of calls Nylas makes to the provider for each GET /v3/grants/<NYLAS_GRANT_ID>/threads request, you might encounter rate limits when working with large threads of email messages. You can take the following steps to avoid rate limits:

• Specify a lower limit to reduce the number of results Nylas returns.
• Add query parameters to your request to filter for specific information.

Provider rate limits

Not all IMAP providers publish information about their rate limits. If you have questions, contact your provider’s customer support team.

Nylas API calls are also subject to the rate limits for the underlying providers, so keep these in mind when you build your Nylas application. The following sections outline the rate limits for common providers.

Google rate limits

As of February 2024, Gmail has new requirements for accounts that send more than 5,000 email messages per day. For more information, see Google’s official documentation.

Google has several sets of rate limits to keep in mind:

• Overall usage limits: 10,000 requests per minute, per application and 600 requests per minute, per user. Google calculates these limits within a one-minute sliding window.
• Message sending limits: 2,000 messages per day (see Google’s Gmail sending limits in Google Workspace documentation).
• Gmail API limits: Per-user rate limit of 250 quota units per second (see Google’s Gmail usage limits documentation).
• Google Calendar API limits: API usage quotas, general usage limits, and operational limits (see Google’s Calendar quotas documentation).

You can log in to the GCP portal and navigate to Enabled APIs and services to see your Google API limits.

Because of a limitation on the provider, a single Nylas request might make multiple calls to Google’s APIs. Nylas returns a Nylas-Provider-Request-Count header that shows the number of calls Nylas made to the Google APIs, and a Nylas-Gmail-Quota-Usage header for requests to the Nylas Messages, Folders, Threads, Attachments, and Drafts APIs that shows how much of your Gmail API quota Nylas used for your request. You can monitor these headers and space out your requests to avoid being rate-limited.

Microsoft rate limits

• Overall usage limits: 10,000 requests per 10-minute period, a maximum of 4 concurrent requests, and a maximum of 150 MB uploaded per 5-minute period (see Microsoft’s Outlook service limits documentation).
• Message sending limits: 30 messages per minute (see Microsoft’s Exchange Online limits documentation).

Because of a limitation on the provider, a single Nylas request might make multiple calls to the Microsoft Graph APIs. Nylas returns a Nylas-Provider-Request-Count header that shows the number of calls Nylas made to the Graph APIs for your request. You can monitor this header and space out your requests to avoid being rate-limited. If Microsoft rate-limits a request, Nylas returns a Retry-After header that shows the number of seconds you have to wait before you can make another request.

EWS rate limits

Your EWS administrator configures the rate limit for your on-prem Exchange server, so Nylas cannot know the server’s actual rate limits. If your Exchange server rate-limits a request, Nylas returns a Retry-After header that shows the number of seconds you have to wait before the server will accept another request.

iCloud rate limits

Apple limits the number of messages you can send to 1,000 per day. For more information, see Apple’s Mailbox size and message sending limits documentation.