Threema

Threema is an end-to-end encrypted messenger developed in Switzerland and sold in three shapes: a paid app for private use, a business edition with central administration, and a self-hosted edition that runs on the customer's own infrastructure. Messages, files and voice, video and group calls are all encrypted end to end, and an account does not require a phone number or an email address: users are identified by a randomly generated Threema ID.

The private app is a one-time purchase of about 6, the exact price depending on the app store and country. For businesses, Work Core costs 3.00 per user per month for up to 200 employees, and Work Professional 5.00 with unlimited employees, one-to-many messaging through Threema Broadcast, API access and premium support; OnPrem is quoted individually and adds a white-labelling option and air-gapped operation, with a 99.9% availability commitment against 99.5% for Core. A 30-day trial covers 30 users with no payment details. The company says more than 8,000 organisations and over 12 million people use Threema, and names EDEKA, Mercedes-Benz and Abiomed among its business customers. Apps exist for iOS, Android, desktop and the web, alongside Threema Libre, a Google-free Android build distributed through F-Droid.

Threema has been developed in Switzerland since 2012, when the first version appeared in Apple's App Store; the company, Threema AG, runs its servers at geographically separated high-security sites in Switzerland with redundancy and failover. The source code is published and reproducible builds let users check that an installed app matches it, with regular external security audits; the company states that there is no advertising, tracking or profiling, and that it is funded by licence sales rather than by user data.