Cwtch vs Delta Chat

Cwtch is a free decentralized messaging app for Android, Linux, macOS, and Windows. Direct conversations use Tor v3 onion services to create anonymous peer-to-peer connections between profiles, and Cwtch says communication is end-to-end encrypted over those services. Both participants must be online for peer-to-peer chat. Group conversations and offline delivery use a third-party server designed to learn as little as possible about message contents or metadata. Group messaging is experimental: users must enable the Experiments and Group Experiment settings, and the project calls metadata-resistant group communication an active research area. Conversation history is not preserved between sessions by default, though it can be enabled for an individual conversation. The protocol is open, allowing bots, services, and interfaces to integrate with Cwtch; core library, Go bindings, and interface code are linked as open source. There is no global display-name registry, which the security handbook says increases impersonation risk. The project recommends version 1.17.2, released October 2, 2026, for security fixes. The plan costs nothing.

Delta Chat is a free, open-source instant messaging app for mobile and desktop, with support for self-hosting. It runs on Android, iOS, Linux, macOS and Windows, and supports multiple profiles and devices. Messages travel through secure, interoperable chatmail relays and are end-to-end encrypted by default, including attachments and their metadata. Delta Chat uses a subset of OpenPGP with Secure-Join and Autocrypt. Servers can still see sender and receiver addresses and message size; other message, contact and group metadata is encrypted. Chats can include interactive web apps for gaming and collaboration. Android and iOS audio and video calls use peer-to-peer WebRTC, but a March 2026 post said the feature was still behind a debug setting. A classic email address can act as a relay only if used exclusively by chatmail clients, and classic email providers generally do not support push notifications. The FAQ says there are no immediate plans for a web client. The project links to a forum for support and feedback.