IMPORTANT: This is a preview version of a future feature of Mailbutler. Please only use this if you want to experiment with potentially unstable functionality and want to provide feedback on your experience.

How does it work?

When you send your emails from your mobile phone via an SMTP server (typically comes in combination with an IMAP server for incoming emails), outgoing messages are delivered through this configured SMTP server. The SMTP server delivers your outgoing emails to the mailbox of the recipients for you.

With Mailbutler's new tracking SMTP relay configured, your emails will first be sent through this SMTP relay, tracking functionality will be added to your email, and it will finally be forwarded to your original SMTP server and delivered as mentioned before.


Using Mailbutler's tracking SMTP relay is only supported when your current email account is sending emails through an SMTP server, which is typically the case for most email accounts that are not Gmail or Outlook accounts.


Important: Please make sure that you copy (or have it accessible somewhere else) the original SMTP server configuration before you replace it with the one below for Mailbutler's tracking SMTP relay.

To configure your email application, e.g. on your mobile phone, to use Mailbutler's tracking SMTP relay, you need to set the following configuration for your email account:

  • Host Name (1):
  • Username (2): <Your Mailbutler account email address>
  • Password (3): <Your Mailbutler account password>

Example for iOS Mail on your iPhone


  1. Open iOS's Settings app and navigate to Mail's Accounts settings (either scroll down or use the search feature at the very top).
  2. Select the email account that you want to change. Navigate further down by selecting the IMAP account. (You should reach the screen depicted in the third screenshot above)
  3. Navigate to the "Outgoing Mail Server" and edit the "Primary Server" with the screen shown in the fourth screenshot above.
    Replace the current values of the three fields "Host Name" (1), "Username" (2), and "Password" (3) with the values above and your Mailbutler account credentials.
  4. Save the SMTP server configuration with the "Done" button. The configuration will be validated by iOS afterwards.

Send your first email through the SMTP relay

Next, head back to your email application and try to send an email. As Mailbutler does not know the configuration of your original SMTP server, you should automatically receive an email to your Mailbutler account email address that asks you to add the required SMTP configuration.

Follow the instructions and enter the server address plus credentials that you were using before you replaced them with the Mailbutler tracking SMTP relay.

Info for Gmail: You might need to create an application-specific password first to allow Mailbutler access to your SMTP account in Gmail. 

After having added your original SMTP configuration as an integration to your Mailbutler account, you can go back to your email application. The email that could not be sent before through Mailbutler's SMTP relay, should now be able to be sent successfully.

This is it!

From now on, whenever you send an email for this email account, it will first go through Mailbutler's tracking STMP relay before it gets immediately delivered through your regular SMTP server.

Try to send your more tracked emails and check whether they appear in Mailbutler's list of tracked emails.


As always, Mailbutler protects your privacy as much as possible. Our tracking SMTP relay does not store or analyze anything about your outgoing emails! It simply attaches the required tracking functionality to your email and stores the basic meta information in your account, so that you can find and monitor the tracked email afterwards.

The rest of the sending process is unchanged and should behave the same way as you know it when not using our SMTP relay.

Having any issues?

As stated above, the tracking SMTP relay is a preview feature and is not yet ready for an official release to all of our users. We would be very happy to receive feedback from you.

Let us know whether you had any difficulties with the setup or experienced any other issues when sending tracked emails from your mobile phone or from other email applications.