# What is MailerCheck?

MailerCheck is an email verification, analysis and list cleaning tool for people who want to optimize their email list and improve email deliverability.

MailerCheck works with all major email marketing tools to improve email deliverability by detecting errors, bounces, catch-all domains, full inboxes and more.

# MailerCheck API

MailerCheck API is RESTful, fully-featured, and easy to integrate with.

You can use your favorite HTTP/REST library that is available for your programming language to make HTTP calls.

# Base URL

All API requests should start with the following base part:



It's important to use HTTPS, otherwise you might experience unexpected results.

# Authentication

Authentication is done by adding an Authorization header to your API request that contains an API token.

In order to use the API token, it needs to be added as Authorization header with the contents of the header being Bearer XXX where XXX is your API token.

This token can be created through the MailerCheck UI by clicking on your profile picture and selecting "API" then click the "Create token" button, give your token a name and that's it.

Authorization: Bearer XXX


Make sure to download or copy your token. You will not be able to see it again after you close the dialog.

Your token is tied to the user that created it, and the account to which it was created under. All the endpoints will use this information and return the proper data.

# API Versions

Any breaking changes made to the API are released as dated, new versions. The current version is 2022-10-01.

By default, all requests made to the MailerCheck API use the latest version, unless the X-Version header is present in the request. To lock down the API version used in your integration, you can provide the current date at the time of your implementation thorugh the X-Version header.

X-Version: 2022-10-01

# API response

MailerCheck follows the REST architectural style for it's API and conforms to generic HTTP response standards.

# HTTP response codes

MailerCheck returns standard HTTP response codes.

Code Name Explanation
200 OK The request was accepted.
201 Created Resource was created.
202 Accepted The request was accepted and further actions are taken in the background.
204 No Content The request was accepted and there is no content to return.
400 Bad Request There was an error when processing your request. Please adjust your request based on the endpoint requirements and try again.
401 Unauthorized The provided API token is invalid.
403 Forbidden The action is denied for that account or a particular API token. Please make sure your account is allowed API access and check your API token permissions.
404 Not Found The requested resource does not exist on the system.
405 Method Not Allowed HTTP method is not supported by the requested endpoint.
408 Request Timeout There is an error on our system. Please contact support (opens new window)
422 Unprocessable Entity There was a validation error found when processing the request. Please adjust it based on the endpoint requirements and try again.
429 Too Many Requests There were too many requests made to the API. Read more on rate limits.
500 Internal Server Error There was an error on our system. Please contact support (opens new window)
502 Bad Gateway There was an error on our system. Please contact support (opens new window)
503 Service Unavailable There was an error on our system. Please contact support (opens new window)
504 Gateway Timeout There was an error on our system. Please contact support (opens new window)

# Rate limits

MailerCheck has a default rate limit of 60 requests per minute on all API endpoints. If you exceed that rate limit, you will receive a 429 error response with a “Too Many Attempts.” message. Please wait for the amount of seconds indicated by retry-after and try again.

Request type Rate limit
All API requests 60 requests/minute

# Example response

HTTP/2 429
content-type: application/json
x-ratelimit-limit: 60
x-ratelimit-remaining: 0
retry-after: 9
x-ratelimit-reset: 1696324073

    "message": "Too Many Attempts."

We try to keep our documentation clear and as simple as possible. If you have something you’d like to see, your feedback (opens new window) is always encouraged.

Last updated: 10/16/2023, 7:55:42 AM