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Add-on icon Colorediffs

Color diffs in the emails you receive. This is typically helpful for reviewing patches formatted with Git or other version control systems.


Get it from Thunderbird's Add-Ons Platform…

Available here

… Or Install it Manually

Pack the add-on as an .xpi file and install it from the “gear” menu in Thunderbird's add-on manager.

On UNIX-like systems, you can create the .xpi file by simply running:

$ cd /path/to/colorediffs/
$ make xpi

Note that this will download (with curl) the latest version of the highlight.js library, which is not included in this repository.


Once installed, the add-on should automatically detect diffs in your plain-text messages and color them with the selected theme. Some options are available in the add-on preference page:

  • You can select the color scheme amongst all the styles supported by highlight.js.
  • You can have tabs and white space characters replaced by visible characters.
  • You can set the length for tab characters (defaults to 8).
  • You can choose to color all plain-text messages (even with no diffs), which is mostly useful to avoid visual discomfort when using a style with a dark background and browsing a mailing list.


Thunderbird 91 and higher require version 2.2.0 or newer.

Version 2+ of the add-on is compatible with Thunderbird stable version 78.4 and onward. It uses the messageDisplayScripts API which was added in Thunderbird 82, and backported to 78.4.

Older versions of the add-on work with Thunderbird up to the version 68.

The distinction is due to Thunderbird's move to MailExtensions. As a consequence of this change, version 2.0.0 of the add-on is a complete rewrite (by Qeole) and works differently from the previous versions. Instead of parsing the diffs and rebuilding the messages itself, the add-on embeds and injects the highlight.js library which takes care of the colors, without reformatting the content of the message.


The project was originally authored by Vadim Atlygin. For a time it has been maintained by Jesse Glick (jglick), and it has now passed to Qeole.

This add-on is mostly in maintenance mode, do not expect new features. Several people are using it to review patches for their daily jobs, so the objective is essentially to keep something basic, but that works.

Nonetheless, you are welcome to report issues or to submit pull requests.