Last updated 11 months ago

Userspace: Sharing Code Between Keymaps

If you use more than one keyboard with a similar keymap, you might see the benefit in being able to share code between them. Create your own folder in users/ named the same as your keymap (ideally your github username, <name>) with the following structure:

  • /users/<name>/ (added to the path automatically)

    • (optional, recommended)

    • (included automatically)

    • config.h (included automatically)

    • <name>.h (optional)

    • <name>.c (optional)

    • cool_rgb_stuff.c (optional)

    • cool_rgb_stuff.h (optional)

All this only happens when you build a keymap named <name>, like this:

make planck:<name>

For example,

make planck:jack

Will include the /users/jack/ folder in the path, along with /users/jack/

!> This name can be overridden, if needed.

The is one of the two files that gets processed automatically. This is how you add additional source files (such as <name>.c) will be added when compiling.

It's highly recommended that you use <name>.c as the default source file to be added. And to add it, you need to add it the SRC in like this:

SRC += <name>.c

Additional files may be added in the same way - it's recommended you have one named <name>.c/.h to start off with, though.

The /users/<name>/ file will be included in the build after the from your keymap. This allows you to have features in your userspace that depend on individual QMK features that may or may not be available on a specific keyboard.

For example, if you have RGB control features shared between all your keyboards that support RGB lighting, you can add support for that if the RGBLIGHT feature is enabled:

ifeq ($(strip $(RGBLIGHT_ENABLE)), yes)
# Include my fancy rgb functions source here
SRC += cool_rgb_stuff.c

Alternatively, you can define RGB_ENABLE in your keymap's and then check for the variable in your userspace's like this:

# Include my fancy rgb functions source here
SRC += cool_rgb_stuff.c

Override default userspace

By default the userspace used will be the same as the keymap name. In some situations this isn't desirable. For instance, if you use the layout feature you can't use the same name for different keymaps (e.g. ANSI and ISO). You can name your layouts mylayout-ansi and mylayout-iso and add the following line to your layout's

USER_NAME := mylayout

This is also useful if you have multiple different keyboards with different features physically present on the board (such as one with RGB Lights, and one with Audio, or different number of LEDs, or connected to a different PIN on the controller).

Configuration Options (config.h)

Additionally, config.h here will be processed like the same file in your keymap folder. This is handled separately from the <name>.h file.

The reason for this, is that <name>.h won't be added in time to add settings (such as #define TAPPING_TERM 100), and including the <name.h> file in any config.h files will result in compile issues.

!>You should use the config.h for configuration options, and the <name>.h file for user or keymap specific settings (such as the enum for layer or keycodes)

Readme (

Please include authorship (your name, github username, email), and optionally a license that's GPL compatible.

You can use this as a template:

Copyright <year> <name> <email> @<github_username>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <>.

You'd want to replace the year, name, email and github username with your info.

Additionally, this is a good place to document your code, if you wish to share it with others.


For a brief example, checkout /users/_example/. For a more complicated example, checkout /users/drashna/'s userspace.

Customized Functions

QMK has a bunch of functions that have _quantum, _kb, and _user versions that you can use. You will pretty much always want to use the user version of these functions. But the problem is that if you use them in your userspace, then you don't have a version that you can use in your keymap.

However, you can actually add support for keymap version, so that you can use it in both your userspace and your keymap!

For instance, lets looks at the layer_state_set_user function. Lets enable the Tri Layer State functionalitly to all of our boards, and then still have your keymap.c still able to use this functionality.

In your <name.c> file, you'd want to add this:

__attribute__ ((weak))
uint32_t layer_state_set_keymap (uint32_t state) {
return state;
uint32_t layer_state_set_user (uint32_t state) {
state = update_tri_layer_state(state, 2, 3, 5);
return layer_state_set_keymap (state);

The __attribute__ ((weak)) part tells the compiler that this is a placeholder function that can then be replaced by a version in your keymap.c. That way, you don't need to add it to your keymap.c, but if you do, you won't get any conflicts because the function is the same name.

The _keymap part here doesn't matter, it just needs to be something other than _quantum, _kb, or _user, since those are already in use. So you could use layer_state_set_mine, layer_state_set_fn, or anything else.

You can see a list of this and other common functions in template.c in users/drashna.

Custom Features

Since the Userspace feature can support a staggering number of boards, you may have boards that you want to enable certain functionality for, but not for others. And you can actually create "features" that you can enable or disable in your own userspace.

For instance, if you wanted to have a bunch of macros available, but only on certain boards (to save space), you could "hide" them being a #ifdef MACROS_ENABLED, and then enable it per board. To do this, add this to your

ifeq ($(strip $(MACROS_ENABLED)), yes)

The OPT_DEFS setting causes MACROS_ENABLED to be defined for your keyboards (note the -D in front of the name), and you could use #ifdef MACROS_ENABLED to check the status in your c/h files, and handle that code based on that.

Then you add MACROS_ENABLED = yes to the for you keymap to enable this feature and the code in your userspace.

And in your process_record_user function, you'd do something like this:

bool process_record_user(uint16_t keycode, keyrecord_t *record) {
switch (keycode) {
case MACRO1:
if (!record->event.pressed) {
SEND_STRING("This is macro 1!");
case MACRO2:
if (!record->event.pressed) {
SEND_STRING("This is macro 2!");
return true;

Consolidated Macros

If you wanted to consolidate macros and other functions into your userspace for all of your keymaps, you can do that. This builds upon the Customized Functions example above. This lets you maintain a bunch of macros that are shared between the different keyboards, and allow for keyboard specific macros, too.

First, you'd want to go through all of your keymap.c files and replace process_record_user with process_record_keymap instead. This way, you can still use keyboard specific codes on those boards, and use your custom "global" keycodes as well. You'll also want to replace SAFE_RANGE with NEW_SAFE_RANGE so that you wont have any overlapping keycodes

Then add #include <name.h> to all of your keymap.c files. This allows you to use these new keycodes without having to redefine them in each keymap.

Once you've done that, you'll want to set the keycode definitions that you need to the <name>.h file. For instance:

#pragma once
#include "quantum.h"
#include "action.h"
#include "version.h"
// Define all of
enum custom_keycodes {
NEW_SAFE_RANGE //use "NEW_SAFE_RANGE" for keymap specific codes

Now you want to create the <name>.c file, and add this content to it:

#include "<name>.h"
__attribute__ ((weak))
bool process_record_keymap(uint16_t keycode, keyrecord_t *record) {
return true;
bool process_record_user(uint16_t keycode, keyrecord_t *record) {
switch (keycode) {
case KC_MAKE:
if (!record->event.pressed) {
#if (defined(BOOTLOADER_DFU) || defined(BOOTLOADER_LUFA_DFU) || defined(BOOTLOADER_QMK_DFU))
":dfu "
":teensy "
":avrdude "
return false;
return process_record_keymap(keycode, record);

This will add a new KC_MAKE keycode that can be used in any of your keymaps. And this keycode will output make <keyboard>:<keymap>, making frequent compiling easier. And this will work with any keyboard and any keymap as it will output the current boards info, so that you don't have to type this out every time.

Additionally, this should flash the newly compiled firmware automatically, using the correct utility, based on the bootloader settings (or default to just generating the HEX file). However, it should be noted that this may not work on all systems. AVRDUDE doesn't work on WSL, namely (and will dump the HEX in the ".build" folder instead).