Codus — Real-Time Collaborative Coding for VS Code

Pair program instantly. No account. No setup. Just a 4-digit code.

Share a room code with your teammate → both editors sync live in seconds.
Built on Yjs CRDTs and Socket.IO — the same real-time stack powering tools like Linear and Notion.

What You Get


Live code sync	Every keystroke appears instantly for every user in the room
Remote cursors	See collaborators' cursors in real time, colour-coded by user
Follow mode	Click a user to auto-scroll and follow their cursor as they move
File awareness	See which file each user is editing; one click to switch to it
Sidebar chat	Send messages, paste selections, share fenced code blocks
Read-only mode	Host can lock the room — great for demos and code review
Deep-link joins	Share one URL that opens VS Code and joins the room directly
No account needed	Works immediately via the shared hosted server

Getting Started

1. Open the Codus panel in the Activity Bar (look for the sidebar icon after installing)

2. Enter your display name and click Create Room

3. Share the 4-digit code — or click Copy Link for a one-click join URL

4. Your collaborator opens Codus, enters the code, clicks Join

Both editors are now synced. Start typing.

Commands

Command	What it does
`Codus: Create Room`	Start a room and become the host
`Codus: Join Room`	Join a room with a 4-digit code
`Codus: Leave Room`	Disconnect from the current room
`Codus: Connection Diagnostics`	Test connectivity to the server

Access all commands via the Command Palette (Ctrl+Shift+P / Cmd+Shift+P).

Settings

Setting	Default	Description
`codus.serverUrl`	`https://codus.onrender.com`	Collaboration server URL. Point this at your own server for a private deployment.

Requirements

VS Code 1.88.0 or newer
Internet connection (or a self-hosted server on your local network)

Free Shared Server

Codus connects to https://codus.onrender.com out of the box — free, no sign-up.

Heads up: The shared server runs on Render's free tier and cold-starts in 20–30 seconds after inactivity. If your first connection times out, wait a moment and retry. Run Codus: Connection Diagnostics to confirm the server is up.

Self-Hosting

Want a private, always-on server for your team? Run your own in minutes.

Requires: Node.js 18+

git clone https://github.com/AllenJohnn/Codus.git
cd Codus && npm install
npm run start -w server          # starts on port 3000
PORT=8080 npm run start -w server  # or pick your own port

Then in VS Code Settings, set codus.serverUrl to http://your-server:3000.

The server exposes GET /health → { "ok": true } for uptime monitoring.

How It Works

Each room holds a Yjs shared document on the server. When you type, your editor produces a compact binary delta — not a full document diff — which the server applies and broadcasts to all other users. Yjs CRDTs guarantee that concurrent edits from different users always merge to the same result, with no conflicts and no data loss.

Rooms are ephemeral: they live in server memory and are destroyed when the last user leaves.

Known Limitations

No persistence — rooms reset if the server restarts. Users must rejoin.
One file at a time — the session syncs the active file. Switching tabs re-binds sync to the new file.
No authentication — anyone with the room code can join. Don't share sensitive code on the public server; self-host instead.

Changelog

0.3.0 — Latest

Free hosted server at https://codus.onrender.com — zero local setup
Codus: Connection Diagnostics command
Fixed WebSocket + polling transport mismatch (works across firewalls and proxies)
Fixed multi-file sync (active file re-binds correctly on tab switch)
Fixed echo deduplication memory leak (TTL-based cleanup)
Socket cleanup on extension deactivation
Chat message size capped at 1 000 characters
Room ID normalisation fix (prevents join failures)

0.2.0

Configurable codus.serverUrl setting
Auto-reconnect with automatic room rejoin
Read-only room mode
Deep-link room joining and shareable links
File awareness, follow mode, remote cursors

0.1.2

Initial release: rooms, live Yjs sync, cursor decorations, sidebar chat

Contributing & Issues

github.com/AllenJohnn/Codus — issues and PRs welcome.

Codus — Collaborative Coding

Allen John