Session vs SimpleX Chat

Session is a decentralized, end-to-end encrypted messaging app for Android, iOS, Linux, macOS, and Windows. Account creation does not require a phone number or email address. Its onion-request routing is designed so no single server knows both the origin and destination of a message. The app supports disappearing messages and encrypted group chats for up to 100 people. Attachments can be up to 10MB; they are encrypted on the device and stored through the Session File Server. Communities are self-hosted public channels, but are not fully end-to-end encrypted. Voice and video calling are beta features for one-to-one calls only, using peer-to-peer networking; calls can expose a user’s IP address to the call partner and an STF-operated STUN/TURN server. The code is open source, and the desktop, Android, and iOS clients have been audited by Quarkslab. The free plan includes encrypted messaging and attachments up to 10MB. Pro costs $2.99 a month and adds messages up to 10,000 characters, unlimited pinned conversations, animated display pictures, and badges.

SimpleX Chat is a messaging application for the SimpleX platform, with apps for Android, iOS, Linux, macOS, and Windows. It supports encrypted text with Markdown and editing, media and file sharing, decentralized groups, voice messages, disappearing messages, and audio and video calls. The network does not assign profile identifiers such as phone numbers or usernames. Messages and metadata use end-to-end encryption with continuous post-quantum key exchange. Four servers participate in each chat so relay servers cannot see which IP addresses communicate. Profiles, contacts, and messages remain in a portable encrypted database on user devices; relay servers hold encrypted messages only until delivery. Users may operate their own servers and still reach people using preconfigured servers. Developers can build bots and integrations using protocol SDKs; the TypeScript SDK connects to the Chat CLI over a WebSocket API. A phone or tablet can link to the desktop app only when both devices share a local network. Disappearing messages and recipient-side deletion are not guaranteed when a recipient device is offline or modified. The free plan costs nothing.