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Getting Started

Life was like a box of chocolates. You never know what you're gonna get.

KMK is a keyboard focused layer that sits on top of CircuitPython. As such, it should work with most boards that support CircuitPython. KMK requires CircuitPython version 7.3 or above. Known working and recommended devices can be found in the list of officially supported microcontrollers

TL;DR Quick start guide

To infinity and beyond! 1. Install CircuitPython version 7.3 or higher on your board. With most boards, it should be as easy as drag and dropping the firmware on the drive 2. Get an up to date copy of KMK from the main branch 3. Unzip it and copy the KMK folder and the file at the root of the USB drive corresponding to your board (often appearing as CIRCUITPY) 4. Create a new or file in the same root directory (same level as with the example content hereunder:

IMPORTANT: adapt the GP0 / GP1 pins to your specific board !


import board

from kmk.kmk_keyboard import KMKKeyboard
from kmk.keys import KC
from kmk.scanners import DiodeOrientation

keyboard = KMKKeyboard()

keyboard.col_pins = (board.GP0,)
keyboard.row_pins = (board.GP1,)
keyboard.diode_orientation = DiodeOrientation.COL2ROW

keyboard.keymap = [

if __name__ == '__main__':
  1. With a wire / paperclip / whatever, connect the pins you selected for col_pin and row_pin together.

feather and keeboar example pins

  1. If it prints the letter "a" (or a "Q" or ... depending on your keyboard layout), you're done!

Now that you're up and running, you may want to go further...

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You're extremely lucky and you have a fully supported keyboard

If your keyboard and microcontroller are officially supported, simply visit the page for your files, and dropping them on the root of the "flash drive". Those pages can be found in the repositories boards folder. You will need the and If you need more detailed instructions on how to customize the configuration settings and key mappings, please refer to the config and keymap documentation.

You've got another, maybe DIY, board and want to customize KMK for it

First, be sure to understand how your device work, and particularly its specific matrix configuration. You can have a look at how key matrices work or read the guide provided by the QMK team for handwired keyboards Once you've got the gist of it: - To start customizing your file, please refer to the config and keymap and keys files respectively, which provide detailed instructions on how to modify the configuration settings and key mappings. - There's a reference of the available keycodes - International extension adds keys for non US layouts and Media Keys adds keys for ... media

And to go even further: - Macros are used for sending multiple keystrokes in a single action - Layers can transform the whole way your keyboard is behaving with a single touch - HoldTap allow you to customize the way a key behaves whether it is tapped or hold, and TapDance depending on the number of times it is pressed

Want to have fun features such as RGB, split keyboards and more? Check out what builtin modules and extensions can do! You can also get ideas from the various user examples that we provide and dig into our documentation.

Pre-compiling KMK for faster boot times or microcontrollers with limited flash

There are two options: 1. To compile KMK yourself you'll need to download and install the compatible mpy-cross for your Operating System. Don't forget to add it to your PATH, test by running mpy-cross from a shell (Powershell, Bash, Fish, etc). Once that's set up, run either make compile (if you have make) or python util/compile.pyto generate the .mpy versions of KMK files. Then copy the whole compiled kmk/ directory to your keyboard.

There are even more compile and copy make targets. Power user can compile KMK and additional libraries, and then load the bytecode and keyboard code onto a keyboard in one go:

make compile copy-compiled copy-board MPY_SOURCES='kmk/ lib/' BOARD='boards/someboard' MOUNTPOINT='/media/user/someboard'
  1. To download a pre-compiled KMK go to Actions > Build on the KMK GitHub project page, click on the latest build, and you'll find the download link at the bottom of the page under Artifacts. Unzip the download and place the contents in the kmk/ directory on your keyboard.

On certain microcontrollers that will still not be enough of a size reduction to fit all of KMK onto the flash (nice!nano for example). You can remove any optional parts of KMK you aren't using. Start by skipping kmk/extensions, kmk/modules, and kmk/quickpin and adding in only the files under those paths used in your keyboard (i.e. files that are imported in your or

Additional help and support

Roads? Where we're going we don't need roads.

In case you need it, debugging help can be found on the debugging page.

For asynchronous support and chatter about KMK, join our Zulip community!

If you ask for help in chat or open a bug report, if possible make sure your copy of KMK is up-to-date. In particular, swing by the Zulip chat before opening a GitHub Issue about configuration, documentation, etc. concerns.