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microsoft/pxt-jacdac 1.8.34 GitHub

Jacdac Services for MakeCode

This project contains Jacdac host and client services for MakeCode editors.

Using this extensions

Supported editors

Developer section

Issues are tracked at .

To build all projects


To bump the release, use the CLI. Don’t create releases from the MakeCode built-in GitHub editors.


Run makecode --pxt-modules to create files in pxt_modules/*, which help with TypeScript auto-completion.

To refresh the constants.ts files, build jacdac-spec (yarn buildspecs from jacdac-ts) from .

Deploying in WSL/Codespaces

If you do not have access to USB drive, launch a local web service and download the built binary.hex

mkc build --watch --serve

then navigate to the firmware web server

Building local projects

Typically you can do makecode` from any subproject to build for micro:bit. To use another config, for example arcade,

makecode -c ../mkc-arcade.json

You can also add --hw d5 or --hw d5,f4,... to build for specific hardware profiles.


This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit

When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

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