Help us make K-9 Mail even better!


Report a bug

Translate the app

K9 Mail uses Transifex for translations. As features are added, there is often a need for translators to localise the text accordingly.

Help other users

Help other users by answering questions on the mailing list.


Get the source

The source code is hosted on GitHub.

Read the development documents

We maintain documentation on the design of the app in the development section of the documentation and on the Wiki. Feel free to contribute towards this and read it to guide patches to submit.

If you are new to Android then the Android Developer site has lots of helpful resources.

Finding issues to fix

A number of the issues are marked with the ‘beginner’ label indicating they are probably suitable for someone with not much experience of K-9.

Developing and submitting a patch


The design of K-9 is constantly evolving. We have recently started to work on formalising our design guidelines for the app in a design repository.


Like everything else, this manual is the work of volunteers. If you feel it could be improved with information on a certain topic, feel free to contribute by creating an issue on the website’s tracker or submitting a pull request.


If you feel like contributing financially, please make a donation to F-Droid, the repository of Free and Open Source Software (FOSS) for the Android platform.