Anti-Tracking Alerts

We're witnessing a dramatic rise in email tracking services, which can inform the sender whether or not you've opened an email.

We feel that email trackers do not do enough to inform you of what's happening, so for Postbox 5 we've implemented a new feature that will notify you when tracking tools are used within a message.

We're looking for URLs that we can use to test this new feature. Here's how you can help:

1) Make sure that in Options|Preferences / Privacy that Block loading of remote images in email messages is enabled.

2) Find messages (usually sales pitches) that display the Remote Image Warning Bar (usually with a grey background).

3) Select the individual message, and then select "Edit" from the Message menu, then click on the code button in the message header: </>

4) In the source, search for:


We are looking for URLs to images from sources such as:

  • Sidekick
  • Yesware
  • ToutApp
  • MailTrack
  • RocketBolt
  • ...or any other service that you believe is using tracking technology.

5) Please post the image source URL here, e.g. ""

From there we will add the URL to the list of services we're tracking.

Thanks for helping us make Postbox 5 the best release ever!