Arc vs Threema
Swiss, paid, anonymous — Arc adds post-quantum + disappearing.
Threema is a respected, audited, anonymous Swiss app with a one-time purchase and no ads. Its main gaps versus Arc are post-quantum cryptography (still research-stage) and granular ephemerality. Arc adds both, plus free E2EE for everyone.
Updated 2026-06-02 · evaluated by Claude Code Opus 4.8 Ultracode
Head-to-head score
Scores from the same independent 9-axis, 100-point rubric used across all 20 messengers. Higher is better.
Arc
89 / 100
Threema
72 / 100
| Axis | Arc | Threema |
|---|---|---|
| Crypto | 18 | 16 |
| Fwd/Bwd Secrecy | 14 | 13 |
| Post-Quantum | 14 | 2 |
| E2EE Coverage | 12 | 12 |
| Sender Privacy | 3 | 7 |
| Registration Privacy | 9 | 10 |
| Ephemeral | 11 | 5 |
| Verification UX | 4 | 4 |
| Multi-Device | 4 | 3 |
Why choose Arc over Threema
01
Post-quantum today: Arc enforces PQXDH (ML-KEM-1024) in production, while Threema's ML-KEM work (with IBM Research) is still research, not deployed (Post-Quantum 14/14 vs 2/14).
02
Dual-layer ephemerality (IGF 3-tier + Mutual Burn) — 11/11 vs Threema's 5 — with timed deletion across every device and server.
03
E2EE is free for everyone on Arc; Threema is a paid app. Plus BLE Mesh offline messaging.
What Threema does well
- Threema has an excellent privacy record: Cure53 audits, formal verification, an anonymous Threema ID (no phone or email), and Swiss jurisdiction with one-time pricing and no ads.
- Registration privacy (10/10) is on par with Arc.
The bottom line
Threema (72) is a top-tier privacy app and a fair fight on anonymity. Arc (89) pulls ahead with production post-quantum cryptography, dual-layer disappearing messages, and free E2EE for everyone.
Get Arc — E2EE, free for everyone
See the full 20-messenger comparison
How Arc's encryption works