Threema. Secure Messenger
Secure. Anonymous. Private.
Developer: Threema GmbH
Purchase date: 23.12.2020 for 1.99 EUR. Threema apps are open source since 21.12.2020! Threema is celebrating with a 50% discount until 28.12.2020.
Purchase price: 3,99 EUR (regular price. One-time, no subscription, no advertising! You do not pay with your personal data!)
Rating: ***** 5 stars
Compatibility: requires iOS or iPadOS 10.0 or higher
Compatible with iPhone, iPad and iPod touch
Languages: German, Basque, English, French, Italian, Dutch, Polish, Portuguese, Russian, Romansh, Spanish, Czech, Turkish.
- Chats and voice messages
- Groups and mailing lists
- Share files, media and locations
- handy survey function
- Voice and video calls
- agree/disagree without Push Notification
- light and dark design according to taste
- also optimised for tablets, can be used without SIM card
- text formatting as you like
- contact verification via QR code to protect against MitM attacks
- chat completely anonymously, no need to enter a telephone number
- Quote function
- Contact synchronisation optional, no address book access required
- Security and Privacy by Design
- End-to-end encryption throughout
- maximum metadata sparseness
- open source and external audits
- anonymous use, no central user account required
- if you grant access to the address book in order to automatically enter the Threema IDs of your address book contacts into Threema, the contact data will only be transmitted in one-way encryption and will not be stored on any data medium at any time
- strong encryption on the device
- chats, contact lists and groups are managed exclusively decentrally on the participating devices, no storage on a server.
In this respect, Threema differs significantly from conventional messengers
- comfortable typing on large keyboard with Threema.Web
- only the client software is open source, not the software on the server
Test Conclusion: highly recommended!
It is not a real disadvantage that Threema's server software is not open source. Thanks to «Security and Privacy by Design» without a central user account with decentralised storage of customer data exclusively on customer devices, Threema's servers only serve as relay stations anyway.
Security experts also recommend Threema as a secure messenger.