SimpleX Chat is a free, private, open-source messenger that uses encryption and does not require user identifiers. It is available on mobile and desktop platforms, including iOS, Android, Windows, macOS, and Linux. After downloading the app, the user creates a profile by entering a display name. The profile is stored locally on the device.

After setup, the app prompts users to choose a notification mode. On first use, it also asks them to enable system protection or set a passcode to secure access. Once an authentication method is selected, the app is ready to use.

Adding contacts

To start chatting, users invite others through a one-time link or a temporary QR code. An optional long-term address can be created for repeated use. When someone uses this address, a connection request is sent and can be accepted or rejected. The address can be set to accept requests automatically. If shared in a profile, group members can connect, and contacts can pass it on to others. The long-term address can be removed at any time without affecting existing connections.

SimpleX Chat supports end-to-end encrypted audio and video calls using WebRTC. Incoming calls can be accepted, rejected, or ignored.

By default, incoming calls appear on the device’s lock screen. This setting can be changed in the app.

SimpleX Chat uses a relay server to keep the IP address hidden during calls. The server can see call duration but not content. Users can choose their own WebRTC relay servers for more control. This setup is stored on the device and must be configured again on a new one

Data management

In the app settings under “Database passphrase and export,” users can choose when messages are deleted. This setting applies only to their device and does not affect other participants.

To back up chats, a passphrase must be set before export. Deleting the chat database removes all messages unless they have been exported.

Files and media stored in the app can be deleted using the “Delete files & media” option without removing messages.

Privacy and security

SimpleX Chat reduces the risk of man-in-the-middle attacks by requiring invitation links to be shared through another channel. That channel can still be compromised, so sharing a QR code during a video call is safer, as it is harder to replace.

Users can verify a connection by comparing a security code with a contact. If both apps show the same code, the connection is trusted. This can be done by scanning, visual comparison, or reading the code during a call.

This check is useful when connecting through group members, since those connections rely on third parties. Verifying the code confirms the connection is secure.

Conclusion

SimpleX Chat is a privacy-focused messaging app that eliminates user identifiers and stores data locally. It protects both message content and metadata, including communication relationships. Users control their data, configure relay servers, and verify connections. It suits those who want secure communication without accounts, phone numbers, or centralized control, while retaining essential messaging features.