Rate Limits

Mailjet APIs are under rate limits for the number of API calls allowed per API keys per second. If you reach a rate limit, our API will return a 429 HTTP error code.

Our transactional APIs (Email and SMS) are offering a high rate limit to accommodate the most demanding messaging needs of our clients. The rate limits for the rest of our Email and SMS APIs (excluding transactional API calls) are much lower, while still allowing a comfortable use of our API by even the most challenging use cases.

To help better deal with these rate limitations, we have put in place Bulk functionalities, helping you increase the quantity of actions you can do with a single call. These functionalities are available for transactional endpoints and contact management endpoints.

When using the Mailjet API, we recommend to:

  • Properly take into account any 429 error (wait and retry)
  • For high frequency use of our API resources, explore the use of our bulk functionalities
  • Separate applications under separate sub accounts