Source Code and Documentation
Desktop App / Threema Web
Build and test instructions can be found in the
README files included in the source-code repositories.
In order to verify that the published source code actually matches the source code the mobile
apps in the stores were built with, we provide
At the moment, reproducible builds are available for Threema’s Android app. Due to
restrictions by Apple, it’s no easy task to offer reproducible builds for iOS, but we are
currently evaluating possible ways to also support reproducible builds for this platform.
For instructions on how to reproduce the published Android app build, please refer to the
Reproducible Builds page.
Bug Reports / Feature Requests / Security Issues
To report bugs or request new features, please contact the Threema support
If you discover a security issue in Threema, please adhere to the coordinated vulnerability disclosure model.
To be eligible for a bug bounty, please file a report on GObugfree (where all the details, including the bounty levels, are listed).
If you’re not interested in the bug bounty program, you can contact us via Threema or by email; for contact details, see threema.ch/contact (section “Security”).
You can contribute to the Threema apps through pull requests on GitHub,
after signing the Contributor License
Agreement. Please refer to the
Submitting Contributions page for more
information. (To translate the Threema app, please don’t create a pull requests; use OneSky instead.)
The Threema apps are subject to the
GNU Affero General Public License
version 3. More details can be found in the source code repositories.
Please note that even though they may be compiled and modified freely, the Threema apps
are still paid apps. An anonymous license check prevents the creation of Threema IDs on
self-compiled apps. If you would like to use a self-compiled app, please restore the backup
of an existing Threema ID. You can create Threema IDs and backups thereof using the purchased app.
If you have questions about the use of self-compiled apps or the license in general,
feel free to contact us. We are publishing the
source code in good faith, with transparency being the main goal. By having users pay for
the development of the app, we can ensure that our goals sustainably align with the goals
of our users: Great privacy and security, no ads, no collection of user data!