Coder has open-sourced a new remote development platform 🥳 Check it out at coder/coder on GitHub.




The prerequisites for contributing to code-server are almost the same as those for VS Code. Here is what is needed:

  • node v14.x
  • git v2.x or greater
  • git-lfs
  • yarn
    • Used to install JS packages and run scripts
  • nfpm
    • Used to build .deb and .rpm packages
  • jq
    • Used to build code-server releases
  • gnupg
  • build-essential (Linux only - used by VS Code)
    • Get this by running apt-get install -y build-essential
  • rsync and unzip
    • Used for code-server releases
  • bats
    • Used to run script unit tests

Creating pull requests

Please create a GitHub Issue that includes context for issues that you see. You can skip this if the proposed fix is minor.

In your pull requests (PR), link to the issue that the PR solves.

Please ensure that the base of your PR is the main branch.

Commits and commit history

We prefer a clean commit history. This means you should squash all fixups and fixup-type commits before asking for a review (e.g., clean up, squash, then force push). If you need help with this, feel free to leave a comment in your PR, and we'll guide you.

Development workflow

yarn watch
# Visit http://localhost:8080 once the build is completed.

yarn watch will live reload changes to the source.

Updates to VS Code

  1. Update the package tag listed in vendor/package.json:
  "devDependencies": {
    "vscode": "cdr/vscode#X.XX.X-code-server"
  1. From the code-server project root, run yarn install. Then, test code-server locally to make sure everything works.
  2. Check the Node.js version that's used by Electron (which is shipped with VS Code. If necessary, update your version of Node.js to match.
  3. Open a PR

Watch for updates to vendor/modules/code-oss-dev/src/vs/code/browser/workbench/workbench.html. You may need to make changes to src/browser/pages/vscode.html.


You can build as follows:

yarn build
yarn build:vscode
yarn release

Run your build:

cd release
yarn --production
# Runs the built JavaScript with Node.
node .

Build the release packages (make sure that you run yarn release first):

yarn release:standalone
yarn test:standalone-release
yarn package

On Linux, the currently running distro will become the minimum supported version. In our GitHub Actions CI, we use CentOS 7 for maximum compatibility. If you need your builds to support older distros, run the build commands inside a Docker container with all the build requirements installed.


There are three kinds of tests in code-server:

  1. Unit tests
  2. Integration tests
  3. End-to-end tests

Unit tests

Our unit tests are written in TypeScript and run using Jest, the testing framework].

These live under test/unit.

We use unit tests for functions and things that can be tested in isolation. The file structure is modeled closely after /src so it's easy for people to know where test files should live.

Integration tests

These are a work in progress. We build code-server and run a script called, which ensures that code-server's CLI is working.

Our integration tests look at components that rely on one another. For example, testing the CLI requires us to build and package code-server.

End-to-end tests

The end-to-end (e2e) tests are written in TypeScript and run using Playwright.

These live under test/e2e.

Before the e2e tests run, we run globalSetup, which eliminates the need to log in before each test by preserving the authentication state.

Take a look at codeServer.test.ts to see how you would use it (see test.use).

We also have a model where you can create helpers to use within tests. See models/CodeServer.ts for an example.

Generally speaking, e2e means testing code-server while running in the browser and interacting with it in a way that's similar to how a user would interact with it. When running these tests with yarn test:e2e, you must have code-server running locally. In CI, this is taken care of for you.


The code-server script serves as an HTTP API for login and starting a remote VS Code process.

The CLI code is in src/node and the HTTP routes are implemented in src/node/routes.

Most of the meaty parts are in the VS Code portion of the codebase under vendor/modules/code-oss-dev, which we describe next.

Modifications to VS Code

In v1 of code-server, we had a patch of VS Code that split the codebase into a front-end and a server. The front-end consisted of the UI code, while the server ran the extensions and exposed an API to the front-end for file access and all UI needs.

Over time, Microsoft added support to VS Code to run it on the web. They have made the front-end open source, but not the server. As such, code-server v2 (and later) uses the VS Code front-end and implements the server. We do this by using a Git subtree to fork and modify VS Code. This code lives under vendor/modules/code-oss-dev.

Some noteworthy changes in our version of VS Code include:

As the web portion of VS Code matures, we'll be able to shrink and possibly eliminate our modifications. In the meantime, upgrading the VS Code version requires us to ensure that our changes are still applied and work as intended. In the future, we'd like to run VS Code unit tests against our builds to ensure that features work as expected.

We have extension docs on the CI and build system.

If the functionality you're working on does NOT depend on code from VS Code, please move it out and into code-server.

Currently Known Issues

  • Creating custom VS Code extensions and debugging them doesn't work
  • Extension profiling and tips are currently disabled

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