Build your own IDE/Tool

This guide will teach you how to build your own Theia-based application. The guide will demonstrate how to configure your own application composed of existing or new Theia extensions, and any VS Code extensions you want bundled in your application by default. Please get familiar with the extension mechanisms of Theia in case you are not already. This guide describes the manual steps to build a Theia-based product, there are two ways to avoid this manual set-up:

We still recommend reading the manual guide first, it allows you to understand the structure of a Theia-based project.


The detailed list of prerequisites is located at the main Theia repository:


Start with creating a new empty directory and moving into it:

mkdir my-app
cd my-app

Create package.json in this directory:

  "private": true,
  "dependencies": {
    "@theia/callhierarchy": "latest",
    "@theia/file-search": "latest",
    "@theia/git": "latest",
    "@theia/markers": "latest",
    "@theia/messages": "latest",
    "@theia/mini-browser": "latest",
    "@theia/navigator": "latest",
    "@theia/outline-view": "latest",
    "@theia/plugin-ext-vscode": "latest",
    "@theia/preferences": "latest",
    "@theia/preview": "latest",
    "@theia/search-in-workspace": "latest",
    "@theia/terminal": "latest"
  "devDependencies": {
    "@theia/cli": "latest"

In a nutshell, Theia applications and extensions are Node.js packages. Each package has a package.json file that manifests package metadata, like name, version, its runtime and build time dependencies and so on.

Let's have a look at the created package:

  • Its name and version are omitted since we are not going to use it as a dependency, and it's marked as private since it is not going to be published as a Node.js package on its own.
  • We've listed required extensions as runtime dependencies, e.g. @theia/navigator.

    • Some extensions require additional tooling installed, in such cases, please consult the corresponding extension documentation.
    • Use this link to see all published extensions.
  • We've listed @theia/cli as a build-time dependency. It provides scripts to build and run the application.

Consuming VS Code Extensions

As part of your application, it is also possible to consume (and package) VS Code extensions. The Theia repository contains a guide on how to include such extensions as part of the application's package.json.

An example package.json may look like the following:

  "private": true,
  "dependencies": {
    "@theia/callhierarchy": "latest",
    "@theia/file-search": "latest",
    "@theia/git": "latest",
    "@theia/markers": "latest",
    "@theia/messages": "latest",
    "@theia/navigator": "latest",
    "@theia/outline-view": "latest",
    "@theia/plugin-ext-vscode": "latest",
    "@theia/preferences": "latest",
    "@theia/preview": "latest",
    "@theia/search-in-workspace": "latest",
    "@theia/terminal": "latest",
    "@theia/vsx-registry": "latest"
  "devDependencies": {
    "@theia/cli": "latest"
  "scripts": {
    "prepare": "yarn run clean && yarn build && yarn run download:plugins",
    "clean": "theia clean",
    "build": "theia build --mode development",
    "start": "theia start --plugins=local-dir:plugins",
    "download:plugins": "theia download:plugins"
  "theiaPluginsDir": "plugins",
  "theiaPlugins": {
    "vscode-builtin-extensions-pack": ""
  "theiaPluginsExcludeIds": [

The following properties are used to consume built-in plugins (bundled extensions):

  • theiaPluginsDir: the relative path to deploy plugins into
  • theiaPlugins: the collection of plugins to download (individual plugins or extension-packs) - can point to any valid download URL (ex: Open VSX, GitHub Releases, etc.)
  • theiaPluginsExcludeIds: the list of plugin ids to exclude when resolving extension-packs


First, install all dependencies.


Second, use Theia CLI to build the application.

yarn theia build

yarn looks up theia executable provided by @theia/cli in the context of our application and then executes the build command with theia. This can take a while since the application is built in production mode by default, i.e. obfuscated and minified.


After the build is finished, we can start the application:

yarn theia start --plugins=local-dir:plugins

or rely on the start script from package.json:

yarn start

You can provide a workspace path to open as a first argument and --hostname, --port options to deploy the application on specific network interfaces and ports, e.g. to open /workspace on all interfaces and port 8080:

yarn start /my-workspace --hostname --port 8080

In the terminal, you should see that Theia application is up and listening:


Open the application by entering the printed address in a new browser page.


Plugins not appearing

If no plugins are available in the running Theia instance, it may be that you need to tell Theia where to find the downloaded plugins. The example above sets the --plugins switch in the start command which should be sufficient. However, if running theia start directly, you can alternatively set an environment variable to achieve the same thing:

export THEIA_DEFAULT_PLUGINS=local-dir:plugins

Building native dependencies behind a proxy

If you run the yarn command behind a proxy you may encounter issues in building native dependencies (like oniguruma), in the last part of the build, with the following error stack:

[4/4] Building fresh packages...
[1/9]  XXXXX
[2/9]  XXXXX
[3/9]  XXXXX
[4/9]  XXXXX
error /theiaide/node_modules/XXXXX: Command failed.
Exit code: 1
Command: node-gyp rebuild
Directory: /theiaide/node_modules/XXXXX
gyp info it worked if it ends with ok
gyp info using node-gyp@3.8.0
gyp info using node@8.15.0 | linux | x64
gyp http GET
gyp WARN install got an error, rolling back install
gyp ERR! configure error
gyp ERR! stack Error: read ECONNRESET
gyp ERR! stack at TLSWrap.onread (net.js:622:25)
gyp ERR! System Linux 3.10.0-862.11.6.el7.x86_64
gyp ERR! command "/usr/bin/node" "/usr/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /theiaide/node_modules/XXXXX
gyp ERR! node -v v8.15.0

This happens because node-gyp does not rely on system/NPM proxy settings. In that case, download the node-headers file using the link provided in the error stack (in the example above and run the build with the following command:

 npm_config_tarball=/path/to/node-v8.15.0-headers.tar.gz yarn install
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