Delta Chat2.57.0

Delta Chat is a free and open source decentralized instant messaging software available on Windows, macOS, Linux, Android and iOS. It creates chat data through chatmail relay by default and does not require binding a mobile phone number; it also supports connecting to compatible traditional email servers. Contacts and groups are mainly established through QR codes or invitation links, and messages are end-to-end encrypted by default.

It is suitable for individuals, small teams and communities who want to reduce dependence on platform accounts and need collaborative chat on desktop and mobile phones. The interface is close to common chat tools, but it does not provide a public user directory, and the first contact usually requires both parties to exchange invitations first. This is a plus for those who value private connections, but it also means migrating contacts requires an extra step.

Core functions

• End-to-end encrypted chat: After establishing a connection using a QR code or invitation link, private and group chats are encrypted by default; chat data is saved on your own device.
• Multiple data and multiple devices: One device can create different data such as work and home, and the same data can also be added to other devices through QR codes. Each device can send and receive messages independently after the migration is completed.
• Group chat and message management: Supports common capabilities such as group, reply, emoticon response, pin, mute, archive, favorite messages, voice messages, pictures and files.
• Message request: Contacts who are not directly invited will enter the request list first, and can have a normal conversation only after accepting it, reducing the interference of unfamiliar messages.
• In-chat apps: You can use interactive web apps to complete mini-games or lightweight collaboration within conversations, with content and invitations still delivered through chat.
• Cross-platform client: Officially maintains desktop and mobile versions, Linux also provides multiple installation methods such as Flatpak, AppImage, DEB, RPM, etc.

Product Features

The idea of Delta Chat is not to build another closed account platform, but to put the chat experience on open standards and optional relays. The default chatmail service simplifies registration, while traditional mail servers leave some room for interoperability. The client and core components are free and open source software. The desktop version adopts GPL-3.0-or-later license. The official simplified Chinese interface is provided and there are no in-app advertisements.

Its limitations also need to be understood in advance: there is no public directory for searching strangers by user name, and contacts usually have to exchange QR codes or links first; the official has not yet provided a formal Web client, and an application needs to be installed on the device. If you switch to a traditional email server, delivery speed, push and unencrypted email compatibility will be affected by the service provider’s configuration. Chat data is mainly saved locally. You should add a second device or export a backup before changing devices.

Installation and usage tutorial

1. Open the Delta Chat official download page and select the platform. For Windows, you can use the Microsoft Store, x64 installer, or portable version; for macOS, you can use the App Store, Homebrew, or DMG; for Linux, Flatpak is preferred, and you can also download AppImage, DEB, or RPM. Install the mobile version from the official app store, F-Droid or the official download page.
2. Create a new chat profile when starting for the first time, fill in the display name and avatar. The default chatmail process will automatically prepare the information required for connection, and there is no need to provide a mobile phone number.
3. Click the QR code button on the main interface and choose to copy or share your invitation link; ask your contacts to scan the QR code directly when face to face. After receiving the remote invitation, open the link with the app and confirm the connection.
4. When you need to use the same data on another device, enter “Settings → Add Second Device” on the original device and keep the two devices on the same LAN; select “Add as Second Device” on the new device and scan the QR code, waiting for the transfer to complete.
5. When dividing identities for work, family, etc., click the profile avatar in the upper left corner and select Add Profile. Different profiles have independent contacts and conversations. Please confirm the current profile before sending a message.
6. When preparing to switch devices or save data for a long time, create a backup file in “Settings → Chat → Export Backup” and properly save the unlocking credentials. The backup contains private chat data and should not be uploaded to a public network drive or sent to others.

Applicable scenarios

• Private chat with family and friends: Create fixed contacts through QR codes without publishing mobile phone numbers or global usernames.
• Small team communication: Process files and long messages on the desktop, receive notifications on the mobile phone, and use multiple materials to distinguish work and private chats.
• Community Groups: Use invitation links to create groups and control the scope of participation through message requests and member invitations.
• Multi-device connection: Computers, mobile phones and tablets can use the same data, suitable for users who often switch between different devices.
• Self-managed communication services: Organizations with operation and maintenance capabilities can choose compatible relays or build their own services, but they need to bear the costs of servers, security updates, and availability.

Free scope and license

Delta Chat client is free to download and use. The desktop version adopts GPL-3.0-or-later license. Major clients such as Android and the chat core are also maintained in a free and open source manner. There are no ads within the app. The default public services can be used directly; if you choose paid email services, hosted chatmail or self-built relays, domain name, server, storage and operation and maintenance costs need to be borne separately.

Usage evaluation

Delta Chat has made the common chat interface, default encryption, multi-data and multi-device more complete, and is very friendly to users who do not want to bind their mobile phone numbers and do not want to start with the command line tool. The official documentation covers installation, invitations, device migration, backup and privacy settings, and the cross-platform installation package is also complete enough.

The threshold for getting started mainly comes from contact invitations and service concepts, rather than the chat operation itself. The lack of public account search and official web version will make recruiting new members and temporary logins for some teams less convenient than mainstream business chat software. It is more suitable for acquaintances, small teams and people who are willing to manage their own communication materials. It is not suitable as a large public community tool that can be joined by clicking on a web page without installation.

Update instructions

The current desktop stable version is 2.57.0, released on July 26, 2026. This version removes the outdated email service provider prompt on the login page, updates the first-time use help, and fixes the problem that the relay list cannot be synchronized to devices of older versions before 2.55.0. When encountering a newly added device that cannot send and receive messages, the official recommendation is to upgrade the main device to 2.57.0 first, and then re-add the second device. The Windows x64 installer is ~133.47 MiB, the macOS universal DMG is ~248.37 MiB, and the Linux x86_64 AppImage is ~142.66 MiB.