Four private messengers, compared on the things that decide which one fits your threat model. Where NoChat is weaker, this page says so.
All four apps encrypt direct messages end to end. They differ in what identifies you, whether your IP address is hidden, how far post-quantum protection goes, whether the code is public, and whether outside auditors have checked it. Signal is the most widely audited and used, but it needs a phone number to register. Session and SimpleX need no phone number and focus on metadata: Session routes traffic through an onion network, and SimpleX has no user identifiers at all. NoChat needs no phone number or email, uses hybrid post-quantum encryption for direct messages, and adds public communities, but its source code is not public and it has not had a third-party audit yet. Facts are as of November 2026.
| NoChat | Session | SimpleX Chat | Signal | |
|---|---|---|---|---|
| Phone number to sign up | Not required | Not required | Not required | Required (a username can hide it from contacts) |
| Email to sign up | Not required | Not required | Not required | Not required |
| What identifies you | An Account ID, plus an optional username | An Account ID (a public key) | No user identifier; contacts connect by one-time link or QR code | Phone number, plus an optional username |
| IP address hidden from the service | Not by default | Yes, onion routing through the Session node network | Optional Tor; private message routing hides your IP from your contacts' servers | No (calls can be relayed to hide your IP from the other person) |
| End-to-end encrypted direct messages | Yes | Yes | Yes | Yes |
| Post-quantum key exchange | Direct messages: hybrid X25519 + ML-KEM-1024. Group chats and calls: classical for now | Not documented | Added to the double ratchet in 2024 | PQXDH (X25519 + ML-KEM) since 2023 |
| Public communities | Yes; community posts are not end-to-end encrypted so the server can rank and search them | Yes (Session Communities) | Public groups via a directory | No; private groups only |
| Source code public | No | Yes | Yes (AGPL) | Yes (AGPL) |
| Independent security audit | None completed yet | Quarkslab, 2021 | Trail of Bits, 2022 (code) and 2024 (protocol design) | Protocol formally analysed by academic researchers; widely reviewed |
| Cost | Free | Free | Free | Free |
Signal needs a phone number to register. Since 2024 you can set a username so contacts do not see the number, but Signal still has it. NoChat, Session and SimpleX Chat all let you sign up with no phone number and no email.
Session is built for this: messages travel through a three-hop onion network, so no single node sees both who you are and where the message goes. SimpleX Chat can route through Tor and, since 2024, relays messages so your contacts' servers do not see your IP. NoChat and Signal do not hide your IP address from their servers by default. If network-level anonymity is your main need, Session or SimpleX with Tor is the stronger choice today.
Signal added PQXDH, a hybrid X25519 and ML-KEM key agreement, in 2023. SimpleX Chat added post-quantum protection to its double ratchet in 2024. NoChat direct messages use a hybrid X25519 + ML-KEM (Kyber-1024) key exchange with ML-DSA-65 signatures on the post-quantum prekeys. NoChat group chats and calls are still classical. The details are on the post-quantum page.
NoChat is for people who want private direct messages without a phone number or email, and also want public communities, stories and video calls in the same app. Pick Signal if you want the most audited app and do not mind giving a phone number. Pick Session if hiding your IP address matters most. Pick SimpleX if you want no identifier of any kind.
NoChat, Session and SimpleX Chat. Signal needs a phone number to register, though a username can hide it from your contacts.
No. The source code is not public today. Session, SimpleX Chat and Signal are open source.
Not yet. No third-party audit has been completed. The cryptography uses standard primitives (AES-256-GCM, X25519, ML-KEM, ML-DSA) and is documented in a crypto inventory.
Not by default. Session sends messages through an onion network. NoChat connects directly to its servers, as Signal does.
No. Direct messages are end-to-end encrypted. Public community posts are stored so the server can rank, search and show them to members.
Free, private by design, and built on auditable cryptography. No phone number, no email required.