Rustpad

Rustpad is an efficient and minimal open-source collaborative text editor based on the operational transformation algorithm. It lets users collaborate in real time while writing code in their browser. Rustpad is completely self-hosted and fits in a tiny Docker image, no database required.

rustpad.io

The server is written in Rust using the warp web server framework and the operational-transform library. We use wasm-bindgen to compile text operation logic to WebAssembly code, which runs in the browser. The frontend is written in TypeScript using React and interfaces with Monaco, the text editor that powers VS Code.

Architecturally, client-side code communicates via WebSocket with a central server that stores in-memory data structures. This makes the editor very fast, allows us to avoid provisioning a database, and makes testing much easier. The tradeoff is that documents are transient and lost between server restarts, or after 24 hours of inactivity.

Development setup

To run this application, you need to install Rust, wasm-pack, and Node.js. Then, build the WebAssembly portion of the app:

wasm-pack build rustpad-wasm

When that is complete, you can install dependencies for the frontend React application:

npm install

Next, compile and run the backend web server:

cargo run

While the backend is running, open another shell and run the following command to start the frontend portion.

npm start

This command will open a browser window to http://localhost:3000, with hot reloading on changes.

Testing

To run integration tests for the server, use the standard cargo test command. For the WebAssembly component, you can run tests in a headless browser with

wasm-pack test rustpad-wasm --chrome --headless

Deployment

Rustpad is distributed as a single 12 MB Docker image, which is built automatically from the Dockerfile in this repository. You can pull the latest version of this image from Docker Hub.

docker pull ekzhang/rustpad

(You can also manually build this image with docker build -t rustpad . in the project root directory.) To run locally, execute the following command, then open http://localhost:3030 in your browser.

docker run --rm -dp 3030:3030 ekzhang/rustpad

We deploy a public instance of this image using DigitalOcean App Platform.

^{All code is licensed under the MIT license.}