Synixir is an Elixir/Phoenix backend for collaborative Yjs documents and shared application state. It syncs changes through Phoenix Channels, uses Yex to work with Yjs on the server, and saves document updates in PostgreSQL.
Connect your own interface with the JavaScript SDK, or try the included playground to edit text, draw, and organize work together.
The playground includes working examples you can use as a starting point:
| Use case | Included examples |
|---|---|
| Write together | CodeMirror text editor and Tiptap rich-text editor |
| Plan projects | Kanban board and flowchart builder |
| Draw together | Excalidraw whiteboard with shared cursors |
| Edit structured data | Multiplayer form and collaborative table |
All examples share room access, presence, and persistence. Each keeps its own content within the room's Yjs document. The playground guide explains the libraries and shared data types.
- Concurrent editing and reconnect support for Yjs text and shared state.
- Durable saves, storage snapshots, compaction, and recovery after server crashes.
- Live participant presence and cursors, with local undo in the playground.
- Accounts, expiring sessions, and owner/editor/viewer room permissions.
- A JavaScript SDK with TypeScript declarations and save status that confirms database persistence.
Start Docker or OrbStack. You'll need Git, Docker Compose v2, OpenSSL, and Elixir 1.18+ with Erlang/OTP 27+. The pinned versions are in .tool-versions. Docker builds the backend and browser examples; the staging scripts need no Mix dependencies.
For a first installation:
git clone https://github.com/arjayby/synixir.git
cd synixir
elixir scripts/staging.exs init
elixir scripts/staging.exs build
elixir scripts/staging.exs upOpen https://localhost:8443 and accept the local self-signed certificate. Create an account and a room, then open the same room in a second tab. Type in either tab to see changes appear in both. Use the example menu to try a board, drawing, or form in that room.
To collaborate with someone else, have them create an account, then grant their username access through Manage access. Sharing a room URL alone grants no access. Wait for Saved before closing a tab with edits.
Stop with elixir scripts/staging.exs stop; start again with
elixir scripts/staging.exs up. Run init only once and retain the private
.local/staging configuration with its database volume. See the
staging guide for certificate renewal, backups, and upgrades.
Use @synixir/client to connect an authorized room and pass its doc and
awareness to your Yjs binding. Use Y.Text for shared text or Y.Map for
application state such as settings and board data.
The SDK is available in this repository and is not published to npm. The SDK guide covers installing a local tarball, account access, editor integration, save states, and cleanup.
- Development and internals: local backend setup, permissions, storage, and checks.
- Client SDK: installation and integration examples.
- Playground: example libraries and frontend development.
- Local Docker staging: HTTPS setup, release checks, and replacement.
- Public playground: Render setup, PostgreSQL, secrets, and deployment checks.
- Operations: quotas, health checks, metrics, alerts, and backup restoration.
Local Docker HTTPS staging, operations tools, and backup restoration are implemented. CI builds the release and runs an HTTPS pilot that checks collaboration, app replacement, and database recovery.
- Runs on one application node, with downtime during upgrades.
- Unsaved offline edits live only in the open tab. Closing or reloading it loses unconfirmed changes.
- Public hosting, external alert delivery, and off-machine backup scheduling require separate setup.
The backend is licensed under AGPL-3.0-or-later. The JavaScript SDK in
packages/client/ and playground examples in examples/collaboration/ are
licensed under Apache-2.0. Third-party components keep their own licenses.
See the licensing policy for scope, self-hosting, and source-sharing
requirements. Paid managed hosting is permitted; self-hosting under the AGPL does
not require a license fee.