Delta Chat vs Session
Delta Chat
delta.chat
Session
getsession.orgSide by side
| Figure | Delta Chat | Session |
|---|---|---|
| Price from | Free | $2.99/mo |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| iOS | Yes | Yes |
| Android | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 2 |
| Spec score · Encrypted Messaging Apps | 8.3 (#4) | 8.3 (#7) |
| Calls | Audio and video calls on Android and iOS use peer-to-peer WebRTC with signaling through Delta Chat messages; the March 2026 post says the feature was still behind a debug setting. | Voice and video calls are beta features, use peer-to-peer networking, and can expose a user’s IP address to the call partner and an STF-operated STUN/TURN server. |
| Headquarters | Freiburg, Germany | Switzerland |
| Platforms | The download page lists Android, iPhone/iPad, macOS, Windows, GNU/Linux, and a community-driven Ubuntu Touch effort. | The maker’s download page offers apps for Android, iPhone, Windows, Mac, and Linux. |
| Product | Delta Chat is a reliable, decentralized and secure instant messaging app for mobile and desktop. | Session is a decentralized, end-to-end encrypted private messaging app. |
| Support | The site links to a Delta Chat forum for support and feedback. | The maker directs users needing help to its support portal. |
Plans
In their own words
Delta Chat
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.
Session
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.