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Synology ChatZulip
Free

License-free, but it requires a Synology NAS to host the server.

 Freemium

The server and clients are free and open source and can be self-hosted at no cost. Zulip…

Windows, macOS, Linux, Android, iOS, Web, Self-hosted Windows, macOS, Linux, Android
  • Messages stay on your own NAS
  • Optional end-to-end encryption for conversations or channels
  • Topic-based threading inside channels, which makes catching up genuinely practical
  • Self-hostable, or hosted, with free plans for open-source communities
  • Only runs on Synology NAS hardware
  • Closed source
  • The topic model takes getting used to and needs team discipline to work
  • The desktop client shares most of its code with the web app, so it inherits its quirks
Downloadable app, Web application, Self-hosted Downloadable app
Closed source Open source
License not stated License: Apache-2.0
Account needed Account needed
Not stated if it works offline Needs internet

Checked October 1, 2026

Checked September 21, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.