Threema. The Secure Messenger

Threema GmbH

About this app

Threema is the world’s best-selling secure messenger and keeps your data out of the hands of hackers, corporations, and governments. The service can be used completely anonymously. Threema is open source and offers every feature one would expect from a state-of-the-art instant messenger. The app also allows you to make end-to-end encrypted voice, video, and group calls. Using the desktop app and the web client, you can also use Threema from your desktop.

PRIVACY AND ANONYMITY
Threema is designed from the ground up to generate as little data on servers as possible. Group memberships and contact lists are managed on your device only and never stored on our servers. Messages are immediately deleted after they have been delivered. Local files are stored encrypted on your mobile phone or tablet. All this effectively prevents the collection and misuse of your personal information, including metadata. Threema is fully compliant with the European privacy legislation (GDPR).

ROCK-SOLID ENCRYPTION
Threema end-to-end encrypts all your communication, including messages, voice and video calls, group chats, files, and even status messages. Only the intended recipient, and nobody else, can read your messages. Threema uses the trusted open source NaCl cryptography library for encryption. The encryption keys are generated and safely stored on the users’ devices to prevent backdoor access or copies.

COMPREHENSIVE FEATURES
Threema is not only an encrypted and private messenger but also versatile and feature-rich.

• Write text and send voice messages
• Make voice, video and group calls
• Share videos pictures and locations
• Send any type of file (pdf animated gif, mp3, doc, zip, etc.)
• Use the desktop app or the web client to chat from your computer
• Create groups
• Conduct polls with the poll feature
• Choose between a dark and a light theme
• Quickly and silently reply with the unique agree/disagree feature
• Verify the identity of a contact by scanning their personal QR code
• Use Threema as anonymous instant messaging tool
• Synchronize your contacts (optional)

SERVERS IN SWITZERLAND
All our servers are located in Switzerland, and we develop our software in-house.

FULL ANONYMITY
Each Threema user receives a random Threema ID for identification. A phone number or email address is not required to use Threema. This unique feature allows you to use Threema completely anonymously – no need to give up private information or to open an account.

OPEN SOURCE AND AUDITS
The source code of the Threema app is open for everyone to review. On top of that, renowned experts are regularly commissioned to conduct systematic security audits of Threema’s code.

NO ADS, NO TRACKERS
Threema is not financed by advertising and does not collect user data.

SUPPORT / CONTACT
For questions or problems please consult our FAQs: https://threema.ch/en/faq

Ratings and reviews

(Edit: Unfortunately, the data backup function for transferring chats from one phone to another is very error-prone and I lost all my group chats in the process. As this is far better with Signal I'm moving to them) The most secure way to chat with friends. You have to pay, but in comparison to WhatsApp not with your data. It would be very useful to be able to select someone as admin in groups, have the option to add more choices to an existing poll, aswell as a smaller font size than "normal".

It's a pity you have to pay before you can even install it because most people will probably pick an alternative. It's already hard enough to convince prople to use Signal instead of Whatsapp, even if it's easily refundable. The one-time charge is more than fair and it's elegible for the family library, too. Priceless features: No necessary binding to a phone number or email address unless you want this. It's also available as Threema Libre from the company outside the Playstore. Recommended.

The app in general is quite good and feels secure. I'm no IT security expert so cannot really verify 😊. Unfortunately, messages and particularly images take a long time to be delivered and sometimes they don't get delivered at all! When sending a single image, the issue only occurs rarely but when sending multiple images at the same time, the issue occurs almost always!

What's new

- Fixed various UI glitches
- GIFs are now rendered using Glide