Graphical User Interface for creating and running Scratch 3.0 projects.
Branch: develop
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paulkaplan Merge pull request #4563 from paulkaplan/fix-tab-toolbox-refresh
Request a toolbox refresh after switching between tabs to fix #4561
Latest commit 1a2c3bd Feb 15, 2019


Scratch GUI is a set of React components that comprise the interface for creating and running Scratch 3.0 projects

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This requires you to have Git and Node.js installed.

In your own node environment/application:

npm install

If you want to edit/play yourself:

git clone
cd scratch-gui
npm install

Getting started

Running the project requires Node.js to be installed.


Open a Command Prompt or Terminal in the repository and run:

npm start

Then go to http://localhost:8601/ - the playground outputs the default GUI component

Developing alongside other Scratch repositories

Linking this code to another project's node_modules/scratch-gui


If you wish to develop scratch-gui alongside other scratch repositories that depend on it, you may wish to have the other repositories use your local scratch-gui build instead of fetching the current production version of the scratch-gui that is found by default using npm install.

To do this:

  1. Make sure you have run npm install from this (scratch-gui) repository's top level
  2. Make sure you have run npm install from the top level of each repository (such as scratch-www) that depends on scratch-gui
  3. From this (scratch-gui) repository's top level, build the dist directory by running BUILD_MODE=dist npm run build
  4. From this (scratch-gui) repository's top level, establish a link to this repository by running npm link
  5. From the top level of each repository that depends on scratch-gui, run npm link scratch-gui
  6. Build or run the repositories that depend on scratch-gui

Instead of BUILD_MODE=dist npm run build you can also use BUILD_MODE=dist npm run watch, however this may be unreliable.

Oh no! It didn't work!

  • Follow the recipe above step by step and don't change the order. It is especially important to run npm first because installing after the linking will reset the linking.
  • Make sure the repositories are siblings on your machine's file tree.
  • If you have multiple Terminal tabs or windows open for the different Scratch repositories, make sure to use the same node version in all of them.
  • In the worst case unlink the repositories by running npm unlink in both, and start over.



You may want to review the documentation for Jest and Enzyme as you write your tests.

See jest cli docs for more options.

Running tests

NOTE: If you're a windows user, please run these scripts in Windows cmd.exe instead of Git Bash/MINGW64.

Before running any test, make sure you have run npm install from this (scratch-gui) repository's top level.

Main testing command

To run linter, unit tests, build, and integration tests, all at once:

npm test

Running unit tests

To run unit tests in isolation:

npm run test:unit

To run unit tests in watch mode (watches for code changes and continuously runs tests):

npm run test:unit -- --watch

You can run a single file of integration tests (in this example, the button tests):

$(npm bin)/jest --runInBand test/unit/components/button.test.jsx

Running integration tests

Integration tests use a headless browser to manipulate the actual html and javascript that the repo produces. You will not see this activity (though you can hear it when sounds are played!).

Note that integration tests require you to first create a build that can be loaded in a browser:

npm run build

Then, you can run all integration tests:

npm run test:integration

Or, you can run a single file of integration tests (in this example, the backpack tests):

$(npm bin)/jest --runInBand test/integration/backpack.test.js

If you want to watch the browser as it runs the test, rather than running headless, use:

USE_HEADLESS=no $(npm bin)/jest --runInBand test/integration/backpack.test.js

Publishing to GitHub Pages

You can publish the GUI to so that others on the Internet can view it. Read the wiki for a step-by-step guide.


We provide Scratch free of charge, and want to keep it that way! Please consider making a donation to support our continued engineering, design, community, and resource development efforts. Donations of any size are appreciated. Thank you!