Mailgun Optimize APIs Overview

Mailgun Optimize by Sinch is a suite of deliverability tools and services that help take the complexity out of email deliverability. Here you will find the API's for Mailgun Optimize.


Below is a list of Mailgun Optimize APIs and an overview of each. Each of these represents a critical aspect of email deliverability and management, ensuring that your email campaigns achieve maximum reach and effectiveness. You will be able to see the various endpoints for each API by clicking on the dropdown for each API on the left sidebar.


Manage domains to monitor reputation. Use these APIs to register domains for domain-based reputation monitoring tools such as Bounce Classification, Spam Trap Monitoring, Domain Blocklist Monitoring,and Google Postmaster tools.

Domain Blocklist Monitoring

Similar to IP blocklist monitoring, this function focuses on keeping an eye on your domain’s presence in blocklists, providing an additional layer of security and reputation management for your email campaigns.

Some of the monitored blocklists include:

  • Spamhaus DBL

Spam Trap Monitoring

Mailgun Optimize identifies and helps you avoid spam traps within your email lists. This feature is essential for maintaining a healthy sender reputation and ensuring that your emails are not flagged as spam.

To learn more about spam traps, read our article, What are Spam Traps.

Google Postmaster Tools

Integration with Google Postmaster Tools allows you to gain insights into how your emails are performing within the Gmail ecosystem. This can include data on spam rates, domain reputation, and other metrics relevant to Gmail.

Bounce Classification

Identify critical bounces sent from Mailgun to quickly and easily identify problems with your sending. Continuing to generate bounces like this will lower your reputation and cause other problems with your sending. Our API classifies these bounces by sending domain and mailbox provider/spam filter. You can pull the logs on an individual bounce to get more details on the specific messages causing these bounces.

IP Blocklist Monitoring

This feature enables you to monitor IP blocklists, allowing you to take immediate action if your IP is listed. This is crucial for maintaining the integrity of your email campaigns and ensuring consistent deliverability.

Monitored blocklists include:

  • SpamCop
  • CBL
  • Spamhaus SBL
  • Spamhaus PBL
  • Spamhaus XBL
  • Barracuda
  • Senderscore BL

Microsoft SNDS (Smart Network Data Services)

This feature provides data and insights into how your emails are being handled by Microsoft’s email services, like Outlook. This includes information on spam filtering and IP status, helping you optimize for one of the world’s largest email service providers.

Inbox Placement

This feature ensures that your emails land in the inbox and not the spam folder. By seed testing your emails, Mailgun Optimize can predict and improve where your emails will appear in various email services, like Gmail, with its tab organization.

Email Preview

This tool allows you to preview your emails across the most popular devices and email clients. It ensures that your emails look exactly as intended, regardless of where and how they are accessed by your recipients.

Creating Tests

When creating a test, all requests must contain a subject property and one source property (html or url). All other properties are optional.

Getting Test Info

When getting test info, the call will return the subject and submission in UNIX timestamp format. It will also contain one to three properties containing any array of clients. The completed property shows clients that have completed screenshots uploaded. The processing property contains clients which are still processd by our system. The bounced property contains clients that were bounced by the destination and cannot be retried.

Getting Test Results

This returns detailed results for screenshots which include their upload locations, send times, completion times, and information about bounces,if any. The URLS in this call are static and will not change for the duration of your active test (90 days from test creation). Any reprocessing that is done will replace the images in these locations. The image locations are generated progammatically before the screenshots are complete. This means that the presence of the URL in the call is not a guarantee that the file will be present. Use the status property to determine whenther or not the file is present in the location, ot ou can manually test the URL provided. If the file is not present, you will receieve a 403 Forbidden response from the endpoint.

Reprocess Screenshots

Sometimes strange things happen on the internet. If a strange result has come back in your screenshot, use this function to tell us to retake screenshots free of charge.

The request should contain and object with a property of clients that contains a list of clients in the TEST_ID provided. The object returned will have a success value indicating if the attemp was successful. If it is false, there will be a reason value describing the failure.

For more on Blocklist Monitoring, see the article, How to Setup Blocklist Monitoring.


Mailgun Optimize provides alerts that notify you of critical issues with your email program, such as blocklistings or other factors that could impact your email deliverability. This enables you to act swiftly to resolve issues.