OSI-licensed only · self-hostable
Discord combines text channels, voice rooms and communities in one app. The open-source options split into three camps: projects that clone the Discord experience, federated Matrix tools, and dedicated voice servers.
Everything below is under an OSI-approved licence we checked in each repository, mostly AGPL-3.0. Several are young and fast-moving, so we flag where a README says self-hosting docs are unfinished.
Licences checked against each repository on November 7, 2026.
| Tool | Best for | Licence | Runs as |
|---|---|---|---|
| Stoat | Discord-style communities with an open backend | AGPL-3.0 | Docker |
| Spacebar | Discord-compatible clients on your own server | AGPL-3.0 | Server |
| Fluxer | A newer free, open chat and VoIP app | AGPL-3.0 | Server |
| Matrix Synapse | Federated rooms with calls | AGPL-3.0 | Server |
| Element Web | The most common Matrix client | AGPL-3.0 | Server |
| Mumble | Low-latency voice chat | BSD-3-Clause | Server |
| Rocket.Chat | Feature-rich chat with federation | MIT | Docker |
Best for: Discord-style communities with an open backend
The services and libraries that power the Stoat chat service. Written in Rust, with REST and WebSocket servers, file and proxy services, and voice via LiveKit, on MongoDB, Redis and MinIO.
Best for: Discord-compatible clients on your own server
Describes itself as a Discord backend re-implementation and extension, with an API, WebSocket gateway, CDN and WebRTC server. Its README says clients designed for Discord.com should generally work, with some incompatibilities.
Best for: A newer free, open chat and VoIP app
Describes itself as a free and open source instant messaging and VoIP chat app for friends, groups and communities. The repo includes API, web app, desktop app, gateway and media proxy modules.
Best for: Federated rooms with calls
An open-source Matrix homeserver written by Element. Matrix is an open standard for interoperable real-time communications, so rooms can span servers.
Best for: The most common Matrix client
A Matrix web and desktop client built with the Matrix JS SDK. Host your own instance by following the install guide. Works with any Matrix homeserver, including Synapse.
Best for: Low-latency voice chat
An open-source voice chat program written on top of Qt and Opus, with an emphasis on low latency and high quality. The mumble-server runs from the command line and an official Docker image exists.
Best for: Feature-rich chat with federation
An open-source, customisable communications platform with end-to-end encryption, federation, voice calls, apps and desktop and mobile clients, deployable with Docker, Podman or Kubernetes.
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| If you need… | Start with |
|---|---|
| The most Discord-like experience | Stoat, Spacebar or Fluxer |
| Keep using existing Discord-style clients | Spacebar |
| Federation with other servers | Matrix Synapse with Element Web |
| Voice only for gaming groups | Mumble |
| A company-friendly chat with admin controls | Rocket.Chat |
Quick answers to common questions
Stoat, Spacebar and Fluxer are the closest to the Discord experience, though each is young. Matrix with Element is the most established federated option, and Mumble is the long-standing choice for voice.
Yes. Spacebar publishes server setup guides, Fluxer has an operator guide, and Matrix Synapse is documented for standalone installs. Stoat's README currently documents a development setup rather than production hosting.
Spacebar says clients designed for Discord.com should generally work with some incompatibilities, but bot compatibility is not claimed in its README. Test your bot before relying on it.
Yes. Synapse and Element Web are both released under the AGPL-3.0, with Element offering a paid commercial licence as an alternative.
Mumble is a dedicated low-latency voice program. Stoat and Matrix-based tools add voice to text chat.
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