Documentation & Resources

A collection of the most important developer resources outside of developer.thunderbird.net.

​
Description
​addons.thunderbird.net​
The official Thunderbird add-on repository.
​Debugging Guide​
A guide from the extension workshop with the most recent information on debugging add-ons. It is written for Mozilla Firefox but applies for Thunderbird as well.
​MailExtension APIs Documentation​
Documentation of all Extension APIs created specifically for Thunderbird. They are called MailExtension APIs to distinguish them from the standard WebExtension APIs inherited from Firefox.
​API documentation for Thunderbird 68​
​API documentation for Thunderbird 78​
​API documentation for Thunderbird 78+​
​Thundernest Sample Extension Repository​
A collection of MailExtensions, showing how to use Thunderbird WebExtension APIs.
​MDN Sample Extension Repository​
A collection of WebExtensions, showing how to use WebExtension APIs. They probably won’t work directly in Thunderbird, but they may provide hints on how to use some of the WebExtension APIs that Thunderbird inherited from Firefox.
​Thundernest Add-On Developer Support Repository​
The add-on developer support repository provides useful code snippets, examples and tools in order to better "weather" the transition to the new extension structure of Thunderbird 78.
​ThunderKdB​
Overall add-on statistics and a very powerful search in the code of all add-ons listed on addons.thunderbird.net (ATN) and a few other public repositories.
​Bugzilla​
Central bug tracking for Mozilla projects. Some useful pages related to Thunderbird:
​List of bugs related to Extension APIs​
​List of all Thunderbird Components​
​Mozilla Developer Documentation (MDN)​
The main documentation for Mozilla developers. As Thunderbird is based on the Mozilla platform, some of the Mozilla documentation is valid for Thunderbird as well. Useful MDN pages on WebExtension are:
​Introduction to WebExtensions​
​manifest.json​
​permissions​
The Mozilla documentation also includes information about internal components and functions used by legacy extensions. Please be aware, that some of those pages are not maintained and are potentially outdated.
​Overview: Mozilla Javascript Code Modules​
​Searchfox​
An online viewer to search the Firefox code base (mozilla-central) and the Thunderbird code base (comm-central). Useful if you still work with legacy add-ons or WebExtension Experiments and need to check how something is implemented in Thunderbird Core. If you are working on a modern MailExtension, you probably never need this.

Adapt to Changes in Thunderbird 69-78

Next - Add-on Development

Developer Community

Last updated 2 weeks ago

	Description
addons.thunderbird.net	The official Thunderbird add-on repository.
Debugging Guide	A guide from the extension workshop with the most recent information on debugging add-ons. It is written for Mozilla Firefox but applies for Thunderbird as well.
MailExtension APIs Documentation	Documentation of all Extension APIs created specifically for Thunderbird. They are called MailExtension APIs to distinguish them from the standard WebExtension APIs inherited from Firefox. API documentation for Thunderbird 68 API documentation for Thunderbird 78 API documentation for Thunderbird 78+
Thundernest Sample Extension Repository	A collection of MailExtensions, showing how to use Thunderbird WebExtension APIs.
MDN Sample Extension Repository	A collection of WebExtensions, showing how to use WebExtension APIs. They probably won’t work directly in Thunderbird, but they may provide hints on how to use some of the WebExtension APIs that Thunderbird inherited from Firefox.
Thundernest Add-On Developer Support Repository	The add-on developer support repository provides useful code snippets, examples and tools in order to better "weather" the transition to the new extension structure of Thunderbird 78.
ThunderKdB	Overall add-on statistics and a very powerful search in the code of all add-ons listed on addons.thunderbird.net (ATN) and a few other public repositories.
Bugzilla	Central bug tracking for Mozilla projects. Some useful pages related to Thunderbird: List of bugs related to Extension APIs List of all Thunderbird Components
Mozilla Developer Documentation (MDN)	The main documentation for Mozilla developers. As Thunderbird is based on the Mozilla platform, some of the Mozilla documentation is valid for Thunderbird as well. Useful MDN pages on WebExtension are: Introduction to WebExtensions manifest.json permissions The Mozilla documentation also includes information about internal components and functions used by legacy extensions. Please be aware, that some of those pages are not maintained and are potentially outdated. Overview: Mozilla Javascript Code Modules
Searchfox	An online viewer to search the Firefox code base (mozilla-central) and the Thunderbird code base (comm-central). Useful if you still work with legacy add-ons or WebExtension Experiments and need to check how something is implemented in Thunderbird Core. If you are working on a modern MailExtension, you probably never need this.