November 8, 2018

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The Threema Web application.

repo name threema-ch/threema-web
repo link
language TypeScript
size (curr.) 65875 kB
stars (curr.) 477
created 2017-02-08
license Other

Threema Web

Build status License Docker Image

Threema Web is a web client for Threema, a privacy-focussed end-to-end encrypted mobile messenger hosted and developed in Switzerland. With Threema Web, you can use Threema on your Desktop without compromising security.


Threema Web establishes a connection between Desktop and mobile device using WebRTC (Android) or encrypted WebSockets (iOS). Signaling and data is end-to-end encrypted with SaltyRTC.

For more information, see the Threema Cryptography Whitepaper.

Bug Reports and Feature Requests

If you find a bug in Threema Web or want to request a new feature, feel free to open an issue on GitHub. Please make sure that your bug report or feature request hasn’t already been filed by using the search function.

Express your personal opinion regarding priority by reacting with :+1: in a particular issue, such as this one. We will factor this in when scheduling what to do next.

Beta Testing

We may occasionally deploy experimental branches on which you are encouraged to test. If you encounter problems, please open an issue and include the experiment’s version number (e.g. 1.2.3-experiment-beta4).


If you want to help translating Threema Web to your language, please check out!


The protocol used to communicate between the Threema app and Threema Web is documented here.


Threema Web is written using TypeScript and AngularJS 1. Dependencies are managed with npm. You currently need Node.js 12 to build Threema Web. (Note that Node.js is only a build dependency, the result is plain old client-side JavaScript.)

Install development dependencies:

npm install

Run the dev server:

npm run devserver

Then open the URL in your browser:

firefox http://localhost:9966

(Note that this setup should not be used in production. To run Threema Web on a server, please follow the instructions at docs/


To run unit tests:

npm run build:unittests && npm run testserver
firefox http://localhost:7777/tests/testsuite.html

To run UI tests:

npm run build  # Required for CSS to be rebuilt
npm run test:ui <browser>

For example:

npm run test:ui firefox
npm run test:ui chrome

You can also filter the test cases:

npm run test:ui firefox emoji

To run linting checks:

npm run lint

You can also install a pre-push hook to do the linting:

echo -e '#!/bin/sh\nnpm run lint' > .git/hooks/pre-push
chmod +x .git/hooks/pre-push


The configuration of Threema Web can be tweaked in src/config.ts:


  • SELF_HOSTED: Set this to true if this instance of Threema Web isn’t being hosted on
  • PREV_PROTOCOL_LAST_VERSION: When the Threema Web protocol version changes, this can be set to the last version of Threema Web that supported the previous protocol version. If set to something different than null, a message will be shown to the user if reconnecting fails.


  • SALTYRTC_HOST: Set this to the hostname of the SaltyRTC server that you want to use. If supplied, the substring {prefix} will be replaced by the first byte of the initiator’s public key, represented as a lowercase hexadecimal value.
  • SALTYRTC_PORT: The port of the SaltyRTC server to be used.
  • SALTYRTC_SERVER_KEY: The public permanent key of the SaltyRTC server. Set this value to null if your server does not provide a public permanent key, or if you don’t want to verify it.


  • ICE_SERVERS: Configuration object for the WebRTC STUN and ICE servers. Each URL may contain the substring {prefix}, which will be replaced by a random byte represented as a lowercase hexadecimal value.


  • PUSH_URL: The server URL used to deliver push notifications to the app.

Self Hosting

For instructions on how to host your own version of Threema Web, please refer to docs/


Contributions to Threema Web are welcome! Please open a pull request with your proposed changes.


Every Threema Web release will be tagged. The git tags are cryptographically signed using the following PGP key:

pub   rsa4096 2016-09-06 [SC] [expires: 2026-09-04]
      E7AD D991 4E26 0E8B 35DF  B506 65FD E935 573A CDA6
uid           Threema Signing Key <>

The public key can be found on Keybase.

If you discover a security issue in the Threema Web, please follow responsible disclosure and report it directly to Threema instead of opening an issue on Github. You can find the security e-mail as well as the PGP public key at


Threema Web license:

Threema Web.

Copyright © 2016-2020 Threema GmbH (

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <>.

For third party library licenses, see LICENSE-3RD-PARTY.txt.

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