In development. RVNT is pre-release — not yet security-audited. Source code, public builds, and the iOS / App Store release aren’t available yet. See the roadmap →

Alternatives

Best Threema alternatives

A paid, Swiss, open-source messenger that needs no phone number and encrypts everything by default, but runs on central servers and isn't yet post-quantum. Here are the more private options, ranked honestly — with the tradeoffs named.

Why people leave Threema

  • It's the only major secure messenger you have to pay for. Threema has no free tier — it's a one-time paid purchase, and because licenses are tied to the app store, switching from Android to iOS means buying it again. For anyone trying to get a whole group or family onto an encrypted app, that paywall is a real adoption barrier that free apps like Signal don't have. (Threema FAQ — Are there recurring costs?)
  • It's not post-quantum yet. Threema's Ibex protocol added forward secrecy, but its encryption is still classical (Curve25519/NaCl). Threema has publicly partnered with IBM Research to integrate NIST-standardized ML-KEM, but that work is ongoing — so a 'harvest now, decrypt later' adversary recording today's traffic isn't yet defeated by the shipping app. (Threema & IBM Research: Collaboration for a Quantum-Secure Future)
  • It still routes through central servers. Threema is privacy-respecting and minimizes stored data, but it is a centralized service — Threema GmbH operates the servers that relay your messages. People who want a fully peer-to-peer, onion-routed, or no-operator design will hit that architectural ceiling. (Threema — Security & data minimization)
  • The network is small. With around 12 million users, Threema is a tiny fraction of WhatsApp's or Telegram's reach, so most of the people you want to message probably aren't on it. That network-effect gap is the most common practical reason people drift to a more widely-used encrypted app. (Threema statistics — over 12 million users)

The alternatives, ranked

  1. 1 Signal the free, audited gold standard

    Free, open-source, independently studied, and now post-quantum, Signal is the safest default for most people leaving Threema — the main trade-off is that it ties your account to a phone number and runs on central servers.

    Compare with RVNT →
  2. 2 Threema (stay) Swiss, no-phone-number, willing to pay

    If your only complaints are price and post-quantum, staying put is reasonable — Threema is Swiss, open-source, needs no phone number, and is independently audited, with PQ work underway via IBM.

    Compare with RVNT →
  3. 3 RVNT no-account, peer-to-peer, post-quantum

    RVNT goes further on architecture — no phone number, no servers storing content, hybrid post-quantum encryption, and Tor-by-default metadata protection — but it's young, unaudited, and pre-release, so it's a fit for early adopters who want the strongest design over a proven track record.

    Get RVNT →
  4. 4 Session anonymity, no phone number

    Onion-routed and requiring no phone number or email, Session hides your IP and metadata by default — but its currently-shipping protocol still lacks forward secrecy, a gap its planned V2 aims to close.

    Compare with RVNT →
  5. 5 SimpleX Chat no identifiers at all

    SimpleX uniquely has no user identifiers — not even random account numbers — using disposable message queues instead, and it's post-quantum, though it's less mature and the UX is rougher than Threema's.

    Compare with RVNT →

Switching from Threema: what to expect

What you keep: Strong end-to-end encryption by default and a no-phone-number identity model are available elsewhere — Session, SimpleX, and RVNT all skip phone numbers entirely, and every option here encrypts messages by default (with the exception that Telegram only does so in opt-in Secret Chats). If you valued Threema's Swiss jurisdiction and independent audits, note that Signal and Session carry comparable audit pedigree, while younger apps like RVNT and SimpleX have not yet completed full independent audits.

What you lose: Threema's chat history doesn't sync to a server, so there's no automatic cloud migration — you'll re-add contacts and start fresh conversations on whatever you move to (this is normal for privacy-first apps and a feature, not a bug). Your Threema ID and any contacts who only use Threema stay behind. If you switch to Signal or WhatsApp you'll trade Threema's anonymous ID for a phone-number-based account; if you go to RVNT, Session, or SimpleX you keep anonymity but join a smaller network with fewer of your existing contacts. And unless you paid for Threema purely to avoid a phone number, moving to a free app like Signal recovers the cost you were paying.

Frequently asked questions

Is Threema actually less secure than free apps like Signal?

No — Threema is genuinely secure: end-to-end encrypted by default, open-source, independently audited (including a well-known 2023 academic analysis by ETH Zurich and Cure53 reviews), and it needs no phone number. The honest gaps versus Signal are that Threema isn't yet post-quantum (Signal is, and Threema is working on it with IBM) and that you have to pay for it. Security-wise they're broadly comparable; the differences are mostly about post-quantum readiness, cost, and network size.

If I leave Threema mainly for privacy, what's the strongest option?

It depends on what you mean by privacy. For metadata and IP-address hiding, Session (onion routing) and RVNT (Tor-by-default plus a mixnet) go further than Threema's centralized servers. For having no account identifier at all, SimpleX is unique. For the best balance of strong, audited, post-quantum encryption with a large user base, Signal is the safest pick — though it does require a phone number. There's no single 'most private' answer; pick based on whether you care most about anonymity, metadata, maturity, or reach.