Try in your browser	Lab	Notebook v7
Binder (Powerful)
JupyterLite (Instant)

A JupyterLab extension to write and load simple JupyterLab plugins inside JupyterLab.

This extension requires JupyterLab 4. Install this extension with pip:

pip install jupyterlab-plugin-playground

Plugin Playground is built to keep the full plugin prototyping workflow inside JupyterLab. In the editor toolbar, you can load the active file as an extension, export the current plugin folder as a starter extension archive, copy a shareable plugin link, and enable per-file Run on save for faster iteration while editing.

The right sidebar includes a single Plugin Playground panel with two collapsible sections. In Extension Points, the Tokens tab helps you discover available token strings and insert import/dependency updates, the Commands tab lets you search command IDs, inspect argument docs, and insert execution snippets (either directly or through AI-assisted prompt mode), and the Packages tab surfaces package docs plus npm and repository links for known modules.

The Extension Examples section lists discovered examples from extension-examples/ and lets you open source entrypoints and README files directly. This keeps reference implementations close while you prototype.

Command completion is also included for app.commands.execute(...) / commands.execute(...) in JavaScript and TypeScript editors, and Notebook v7 integrates Start from File, Build with AI, and Take the Tour into New-file flows so you can create starter plugin files from the tree interface.

The Launcher Plugin Playground section includes Start from File, Build with AI, and Take the Tour so first-time users can pick a guided flow quickly.

To regenerate the screenshots used in this README:

jlpm docs:screenshots

1. Optional first-time walkthrough: run Take the Tour from the Launcher or Command Palette.
2. Create a file with Start from File (Command Palette or Notebook v7 New menu).
3. Paste plugin code into the active editor.
4. Run Load Current File As Extension from the editor toolbar or Command Palette.
5. Use the Run on save icon button for fast iteration on one file.
6. Use the sidebar to discover tokens, commands, packages, and extension examples.

For extension examples availability:

• For source checkouts: run git submodule update --init --recursive.
• PyPI installs: bundled examples are copied into extension-examples/ automatically when the server extension starts.

When reloading a plugin with the same id, Plugin Playground attempts to deactivate and deregister the previous plugin before loading the new one. Defining deactivate() is still recommended for clean reruns.

As an example, open the text editor by creating a new text file and paste this small JupyterLab plugin into it. This plugin creates a simple command My Super Cool Toggle in the command palette that can be toggled on and off.

import { ICommandPalette } from '@jupyterlab/apputils';

const plugin = {
  id: 'my-super-cool-toggle:plugin',
  autoStart: true, // Activate this plugin immediately
  requires: [ICommandPalette],
  activate: function (app, palette) {
    let commandID = 'my-super-cool-toggle:toggle';
    let toggle = true; // The current toggle state
    app.commands.addCommand(commandID, {
      label: 'My Super Cool Toggle',
      isToggled: function () {
        return toggle;
      },
      execute: function () {
        // Toggle the state
        toggle = !toggle;
      }
    });

    palette.addItem({
      command: commandID,
      // Sort to the top for convenience
      category: 'AAA'
    });
  }
};

export default plugin;

While in the text editor, load this plugin in JupyterLab by invoking the Command Palette and executing Load Current File As Extension. Invoke the Command Palette again and you will see a new command "My Super Cool Toggle". Executing this new command will toggle the checkbox next to the command.

As another more advanced example, we load the bqplot Jupyter Widget library from the cloud using RequireJS. This assumes you have the ipywidgets JupyterLab extension installed.

// IJupyterWidgetRegistry token is provided with Plugin Playground
import { IJupyterWidgetRegistry } from '@jupyter-widgets/base';
// Use RequireJS to load the AMD module. '@*' selects the latest version
// and `/dist/index.js` loads the corresponding module containing bqplot
// from the CDN configured in Settings (`requirejsCDN`).
import bqplot from 'bqplot@*/dist/index';

const plugin = {
  id: 'mydynamicwidget',
  autoStart: true,
  requires: [IJupyterWidgetRegistry],
  activate: function (app, widgets: IJupyterWidgetRegistry) {
    widgets.registerWidget({
      name: 'bqplot',
      version: bqplot.version,
      exports: bqplot
    });
  }
};
export default plugin;

There are a few differences in how to write plugins in Plugin Playground compared to writing a full JupyterLab extension:

• The playground is more forgiving: you can use JavaScript-like code rather than strictly typed TypeScript and it will still compile.
• You can load a plugin with a given id more than once during iteration. Plugin Playground attempts to deactivate and deregister the previous version before registering the new one. Defining deactivate() in your plugin is still recommended for predictable cleanup between reloads.
• To load code from an external package, RequireJS is used (hidden behind ES module-compatible import syntax), so import statements may need explicit version or file paths.
  • In addition to JupyterLab and Lumino packages, only AMD modules can be imported; ES modules and modules compiled for Webpack/Node are not supported directly and can fail with Uncaught SyntaxError: Unexpected token 'export'.
• The playground can import relative files (.ts, .tsx, .js, and .css), load SVG as strings, and load settings schema from package.json (jupyterlab.schemaDir) with plugin.json fallback for single-plugin prototyping.

Version 0.3.0 supported only object-based plugins and require.js based imports. While the object-based syntax for defining plugins remains supported, using require global reference is now deprecated.

A future version will remove require object to prevent confusion between require from require.js, and native require syntax; please use requirejs (an alias function with the same signature) instead, or migrate to ES6-syntax plugins. Require.js is not available in the ES6-syntax based plugins.

To migrate to the ES6-compatible syntax:

• assign the plugin object to a variable, e.g. const plugin = { /* plugin code without changes */ };,
• add export default plugin; line,
• convert require() calls to ES6 default imports.

Plugin Playground supports AI-assisted extension prototyping in both JupyterLite and Binder deployments.

• In JupyterLite, you can use browser-based AI chat and completions.
• In Binder (JupyterLab), you can use the same JupyterLite AI tooling.

1. Launch Plugin Playground in Lite or Binder (or start with the Take the Tour tile).
2. Open the AI settings panel.
3. Add a provider and choose a model.
4. Enter your provider API key and save.
5. Ask the assistant to draft or refine plugin code, then run Load Current File As Extension.

• JupyterLite AI documentation
• Plugin authoring skill for agents

In the Commands tab, each command row includes a split + action and a mode dropdown:

• Insert in selection inserts:

  app.commands.execute('<command-id>');

  at the active cursor position in the current editor.

• Prompt AI to insert does not insert directly. It opens JupyterLite AI chat and prefills a contextual prompt so AI can choose a better insertion location before you submit.

The same command row also includes the f(n) button to inspect command argument docs inline before insertion.

The sidebar remembers your last-used command insert mode in:

• commandInsertDefaultMode (insert or ai, insert by default)

Plugin Playground exposes command APIs for scripting, agents, and automation:

• plugin-playground:create-new-plugin (supports optional { cwd?: string, path?: string })
• plugin-playground:take-tour (supports optional { cwd?: string, path?: string })
• plugin-playground:load-as-extension
• plugin-playground:open-js-explorer
• plugin-playground:list-tokens (supports optional { query?: string })
• plugin-playground:list-commands (supports optional { query?: string })
• plugin-playground:list-extension-examples (supports optional { query?: string })
• plugin-playground:export-as-extension (supports optional { path?: string, format?: 'zip' | 'wheel' })
• plugin-playground:share-via-link (supports optional { path?: string, useBrowserSelection?: boolean, useContextTarget?: boolean })

Example:

await app.commands.execute('plugin-playground:create-new-plugin', {
  cwd: 'my-extension/src',
  path: 'index.ts'
});

await app.commands.execute('plugin-playground:list-tokens', {
  query: 'notebook'
});

await app.commands.execute('plugin-playground:export-as-extension', {
  path: 'my-extension/src/index.ts'
});

await app.commands.execute('plugin-playground:export-as-extension', {
  path: 'my-extension/src/index.ts',
  format: 'wheel'
});

await app.commands.execute('plugin-playground:share-via-link', {
  path: 'my-extension'
});

plugin-playground:share-via-link shares a file or folder. If no path is provided, it shares the active file. The file/folder right-click context-menu entries use the selected browser item path automatically. Shared payload tokens are encoded in the URL fragment (#plugin=...) to avoid common query-string/request-line size limits. In the editor toolbar, the Share action is a dropdown with Share Single File and Share Package; package sharing is enabled when a package.json is found in the current file directory or its parent directory. Folder sharing excludes common non-exportable files by default (for example media assets, README/docs files, and test/spec files), but you can include them manually from the selection dialog. By default, folder sharing always opens a file-selection dialog so you can exclude files before creating the link. You can control this with shareFolderSelectionDialogMode (always, auto-excluded-or-limit, or limit-only). If the generated URL is too long, you can pick a smaller subset of files in the same dialog. The same action is also available from the IPluginPlayground API via shareViaLink(path?).

When opening a shared URL, Plugin Playground restores the shared file(s) and opens one restored file, but does not execute it automatically. Run Load Current File As Extension when you are ready.

List commands (list-tokens, list-commands, list-extension-examples) return a JSON object with:

• query: the filter text that was applied
• total: total number of available records
• count: number of records returned after filtering
• items: matching records

export-as-extension defaults to ZIP and also supports Python wheel (format: 'wheel'). export-as-extension and share-via-link return operation-specific metadata (for example, success status, paths, counts, URL length, and optional message).

Plugin Playground settings are available in Settings > Settings Editor > Plugin Playground. These settings are intended to support both quick experiments and repeatable startup workflows.

Runtime import resolution order is:

1. Known modules (KNOWN_MODULE_NAMES / static map)
2. Module Federation (shared scopes and federated extension modules)
3. Local/relative file imports
4. CDN (RequireJS), if allowed by policy

allowCDN controls whether unknown packages can be executed from a CDN. The default awaiting-decision mode keeps things explicit, while always-insecure and never let you enforce a fixed policy.

requirejsCDN defines the base URL used by RequireJS to resolve unknown package imports (for example https://cdn.jsdelivr.net/npm/). If you rely on external AMD packages in prototypes, this setting determines where those packages are fetched from.

loadOnSave enables automatic load-as-extension behavior on save for supported editor files (JavaScript and TypeScript). This is useful when iterating quickly without repeatedly triggering the load command manually.

commandInsertDefaultMode sets the default behavior for the + action in the Commands tab (insert for direct insertion or ai for AI-assisted prompt flow).

shareFolderSelectionDialogMode controls when folder sharing prompts for file selection (always, auto-excluded-or-limit, limit-only).

For startup automation, there are two complementary settings:

• urls is a list of plugin URLs that are fetched and loaded at startup. This is useful for hosting a plugin source file externally (for example, a gist or internal text endpoint) and keeping clients in sync.
• plugins is a list of plugin source strings loaded at startup. This is useful for embedding short startup plugins directly in settings. Because these are JSON strings, multiline code must encode line breaks as \n\.

Example:

{
  allowCDN: 'awaiting-decision',
  requirejsCDN: 'https://cdn.jsdelivr.net/npm/',
  loadOnSave: false,
  commandInsertDefaultMode: 'insert',
  urls: ['https://gist.githubusercontent.com/.../raw/plugin.ts'],
  plugins: [
    "{ \n\
      id: 'MyConsoleLoggingPlugin', \n\
      autoStart: true, \n\
      activate: function(app) { \n\
        console.log('Activated!'); \n\
      } \n\
    }"
  ]
}

The playground deployments include jupyterlab-open-url-parameter, so you can open files directly from URL query parameters with fromURL.

Use raw GitHub links pinned to a commit SHA (not github.com/.../blob/... links), for example:

https://jupyterlab-plugin-playground.readthedocs.io/en/latest/lite/lab/index.html?fromURL=https://raw.githubusercontent.com/<org>/<repo>/<commit-sha>/<path-to-file>

Replace <commit-sha> with the exact commit you want to lock to.

You can repeat fromURL to open multiple files in one launch.

You will need NodeJS to build the extension package.

# Clone the repo to your local environment
# Change directory to the jupyterlab-plugin-playground directory
# Install package in development mode
pip install -e .
# Link your development version of the extension with JupyterLab
jupyter labextension develop . --overwrite
# Rebuild extension Typescript source after making changes
jlpm run build

Install and enable hooks:

python -m pip install pre-commit
pre-commit install

Run all configured hooks once after setup:

pre-commit run --all-files

Useful commands:

• pre-commit run --files <path ...>: run hooks for specific files only.
• pre-commit autoupdate: update pinned hook versions.

You can watch the source directory and run JupyterLab at the same time in different terminals to watch for changes in the extension's source and automatically rebuild the extension.

# Watch the source directory in one terminal, automatically rebuilding when needed
jlpm run watch
# Run JupyterLab in another terminal
jupyter lab

With the watch command running, every saved change will immediately be built locally and available in your running JupyterLab. Refresh JupyterLab to load the change in your browser (you may need to wait several seconds for the extension to be rebuilt).

By default, the jlpm run build command generates the source maps for this extension to make it easier to debug using the browser dev tools. To also generate source maps for the JupyterLab core extensions, you can run the following command:

jupyter lab build --minimize=False

Integration tests live in ui-tests (Playwright + Galata).

Run from repository root:

jlpm run build:prod
jlpm run test:integration
jlpm run docs:screenshots

setup:

cd ui-tests
jlpm install
jlpm playwright install chromium

See ui-tests/README.md for focused test commands.

pip uninstall jupyterlab-plugin-playground

In development mode, you will also need to remove the symlink created by jupyter labextension develop command. To find its location, you can run jupyter labextension list to figure out where the labextensions folder is located. Then you can remove the symlink named @jupyterlab/plugin-playground within that folder.

See RELEASE