- Category
- Messaging · SaaS alternative
- Cost
- Paid
- Country
- Switzerland
- Licensing
- Mixed
- Platforms
- iOS · Android · Linux · macOS · Windows · Web
Pros and cons
+ what works
- +No phone number or email required to register
- +One-time purchase around 6 CHF with no recurring subscription for the private app
- +Swiss jurisdiction and Swiss-hosted servers
- +AGPL-3.0 clients with reproducible builds for iOS and Android
− watch out for
- −Server source code is not public; only the clients are open
- −User base is small compared to Signal or WhatsApp, so many contacts are not reachable
- −2022 ETH Zurich analysis found seven cryptographic flaws in the legacy protocol; Threema patched and replaced it with Ibex, but the episode is worth knowing
- −Paying up front is a friction point for casual contacts
Privacy notes
Messages, calls, and group chats are end-to-end encrypted by default using NaCl primitives layered into Threema's "Ibex" protocol, rolled out after the 2022 ETH Zurich disclosure. Accounts are identified by an 8-character Threema ID generated on-device, with no phone number or email required. Servers are operated in Switzerland and hold ciphertext plus minimal routing data. Threema GmbH is headquartered in Pfäffikon, Switzerland and operates under Swiss data protection law. Clients are AGPL-3.0 with reproducible builds for iOS and Android; the server stack remains closed source.
Tags
#e2ee · #swiss · #paid-once · #no-phone-number
Comments (1)
Sadly not that widely used in CH