micro:bit LabOpen editor →

MAKE, TEST, DOWNLOAD

Your offline micro:bit lab

Create projects in Blocks, JavaScript, or MakeCode Python. The simulator and the bundled micro:bit V1/V2 firmware runtimes run from this Mabni server. No Microsoft sign-in or internet connection is needed.

Connect and download

  1. Use a USB data cable. A charging-only cable will not work.
  2. In MakeCode, choose Download, then follow the pairing steps. Select your micro:bit in the browser’s device chooser.
  3. If pairing is unavailable, choose Download as File. Copy the downloaded .hex file onto the MICROBIT drive in your file explorer.
  4. Wait for the board’s transfer light to finish flashing before unplugging it.

Direct USB pairing requires Chrome or Edge and a secure browser context: localhost on the computer running Mabni, or a trusted HTTPS classroom server. A classroom address such as http://192.168… supports the editor and HEX downloads, but the browser does not allow WebUSB there.

Keep your projects

MakeCode saves projects in this browser on this device. Download your HEX file as a backup. To reopen it, go to MakeCode Home → Import → Import File. The file contains your program as well as firmware. On a shared computer, use a separate browser profile for each learner, or import and export the learner’s HEX at the start and end of a session.

What is available offline?

The editor, simulator, standard blocks, JavaScript/Python conversion, local projects, and HEX compilation are bundled. Radio, buttons, LED display, music, sensors, and standard pin controls are included. Physical sensors and radio communication can only be fully tested on real boards.

Cloud accounts, online sharing, GitHub imports, internet extension search, and online galleries are disabled. Additional C++ extensions require a separately prepared firmware runtime; downloading an arbitrary extension is not an offline capability. MakeCode Python runs on the MakeCode runtime; it is different from MicroPython.

My board does not appear

Try a known USB data cable and another USB port. Check for a MICROBIT drive. Direct pairing lists devices only after you open the browser’s chooser and grant access. If the board firmware is too old for WebUSB, use the HEX file method. Do not install drivers from unknown websites.

The file downloaded, but I cannot test a board

You can keep coding with the simulator. Successful compilation confirms that a HEX file was generated; it does not confirm that a physical board was flashed.

Version and credits

Microsoft MakeCode for micro:bit 9.1.1, PXT core 13.0.1. Packaged locally for Mabni with cloud services and analytics disabled. The upstream editor and simulator retain their identity. Mabni is not an official Microsoft or micro:bit product.

micro:bit target license · PXT core license · Third-party notices