A Blocks / JavaScript code editor for the micro:bit built on PXT

micro:bit target for PXT

This target allow to program a BBC micro:bit using PXT (Microsoft Programming Experience Toolkit).

Build Status

Issue tracking

All issue tracking for this repo happens at https://github.com/Microsoft/pxt, see you there!

Local server

The local server allows to run the editor and the documentation from your computer.


The following commands are a 1-time setup after synching the repo on your machine.

  • See requirements for pxt
  • clone this repo to your computer and go in the project folder git clone https://github.com/microsoft/pxt-microbit cd pxt-microbit
  • install the PXT command line (add sudo for Mac/Linux shells). npm install -g pxt
  • install the dependencies npm install


Run this command to open a local web server (add sudo for Mac/Linux shells)

pxt serve

If the local server opens in the wrong browser, make sure to copy the URL containing the local token. Otherwise, the editor will not be able to load the projects.

If you need modify the .cpp files, turn on yotta compilation with the -yt flag (add sudo for Mac/Linux shells):

pxt serve -yt


To update your PXT version and make sure you’re running the latest tools, run (add sudo for Mac/Linux shells)

pxt update

More instructions at https://github.com/Microsoft/pxt#running-a-target-from-localhost


The build automatically runs the following:

  • make sure the built-in packages compile
  • pxt run in libs/lang-test* - this will run the test in command line runner; there is a number of asserts in both of these
  • pxt testdir in tests - this makes sure all the files compile and generates .hex files
  • run the TD->TS converter on a number of test scripts from microbit.co.uk and make sure the results compile

To test something on the device:

  • do a pxt deploy in libs/lang-test* - they should show 1 or 2 on the screen (and not unhappy face)
  • run pxt testdir in tests and deploy some of the hex files from tests/built

The lang-test0 source comes from the pxt-core package. It’s also tested with pxt run there.

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.

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A Blocks / JavaScript code editor for the micro:bit built on PXT ...