API Use Policy

You may use the API solely as described in this Policy to use MailerSend services and build integrations.

Last updated on May 20, 2024

The MailerSend API Use Policy ("Policy") is a part of the MailerSend Terms of Use ("ToU"). MailerSend has developed and provides access to the API that may be used to access transactional email services ("Services"). You may use the API solely as described in this Policy to use MailerSend services and build integrations. All API requests are subject to this Policy, including all the  API endpoints, the SMTP relay and the inbound requests, and they are collectively referred to as the “API”.

Please note that throughout the Policy, "we," "us," and "our" refer to MailerSend, and "you," "your," and "yours" refer to the user.

This Policy enters into force (a) from the day you agreed with our ToU and continues for an indefinite period of time; or (b) on March 23, 2022 if you became our client before March 23, 2022 and continues for an indefinite period of time.

If there is any conflict between this Policy and the ToU, the relevant terms of the ToU shall take precedence.

1. Login to API

You can access our API using one of your account’s API tokens. Your users might log in using their API token. Users will not need to provide you with their MailerSend username or password to log in. 

2. Privacy Requirements

You will comply with all applicable privacy laws and regulations including those applying to personal data. You will provide and adhere to a privacy policy that clearly and accurately describes to users what user information you collect and how you use and share such information. Any user data that is collected by MailerSend via your integration will be treated in accordance with our Privacy Policy

3. Allowable Use

MailerSend does not allow you to use the API for sending spam or taking any other actions that violate our ToU. You are not allowed to attempt to hack or change the way in which the Service or API function.  

4. Abuse

We have API limits in place by the endpoint (rate limits) and for our whole API (daily quota). Hitting one of these limits is considered an excessively frequent request to MailerSend. If this occurs, we will tell you  the problems with how you are interfacing with our API. However, if the abuse is too big to handle, we have the right to temporarily or permanently suspend your account with or without notice immediately. We are not required to provide you with a refund if we deem it necessary to restrict your access due to API abuse.

5. License

Subject to your compliance with this Policy, we grant you a limited, non-exclusive, non-sublicensable, non-transferable, non-assignable license to use the API to develop, test, operate and support your integration, and distribute or allow access to your integration to users of your service. You have no right to distribute or allow access to the API as a stand-alone product.

6. Ownership rights

You acknowledge that MailerSend owns all rights, title and interest in and to the Service and the API, including without limitation all intellectual property rights, and such rights are protected by international intellectual property laws. All rights not expressly granted in this Policy are withheld. You agree that you will not copy, reproduce, alter, modify, or create derivative works from the Service and the API. You own all worldwide rights, titles, and interest in the integration, except for the API, our marks, and the Service (including all intellectual property rights). If you provide feedback or suggestions about the API or the Services, then we may use such information without obligation to you.

7. Security

You are responsible for implementing and maintaining appropriate technical and organizational security measures to protect and preserve the security and confidentiality of the data of your users. You must promptly report any security vulnerabilities or security incidents that you discover in writing via email to

8. Confidentiality 

You may have access to confidential information specific to the Services or API. You are only allowed to use this information to build integrations with the API. You will protect this confidential information from unauthorized use and disclosure.

9. Termination

We may limit your use of the API at any time. We may monitor your use of the API for compliance with these rules, and we may deny you access to the API if you violate it. We may terminate your access to our API at any time for any reason. 

10. Disclaimer 

We provide the API as-is. That means we don’t provide warranties of any kind, either express or implied, including but not limited to merchantability and fitness for a particular purpose. MailerSend is not responsible to you or any third party for unauthorized access to your customer data or for unauthorized use of the Services or API that is not solely caused by MailerSend’s failure to meet its security obligations as set in Privacy Policy.

11. Changes

MailerSend reserves the right to change this API Use Policy at any time. If we decide to change this document, we will post changes on this page. All changes are effective immediately upon posting and we suggest that you check this API Use Policy periodically.