Basic Keycodes
The basic set of keycodes are based on the HID Keyboard/Keypad Usage Page (0x07) with the exception of KC_NO, KC_TRNS and keycodes in the 0xA5-DF range. See below for more details.
Letters and Numbers
| Key | Description | 
| KC_A | aandA | 
| KC_B | bandB | 
| KC_C | candC | 
| KC_D | dandD | 
| KC_E | eandE | 
| KC_F | fandF | 
| KC_G | gandG | 
| KC_H | handH | 
| KC_I | iandI | 
| KC_J | jandJ | 
| KC_K | kandK | 
| KC_L | landL | 
| KC_M | mandM | 
| KC_N | nandN | 
| KC_O | oandO | 
| KC_P | pandP | 
| KC_Q | qandQ | 
| KC_R | randR | 
| KC_S | sandS | 
| KC_T | tandT | 
| KC_U | uandU | 
| KC_V | vandV | 
| KC_W | wandW | 
| KC_X | xandX | 
| KC_Y | yandY | 
| KC_Z | zandZ | 
| KC_1 | 1and! | 
| KC_2 | 2and@ | 
| KC_3 | 3and# | 
| KC_4 | 4and$ | 
| KC_5 | 5and% | 
| KC_6 | 6and^ | 
| KC_7 | 7and& | 
| KC_8 | 8and* | 
| KC_9 | 9and( | 
| KC_0 | 0and) | 
F Keys
| Key | Description | 
| KC_F1 |  | 
| KC_F2 |  | 
| KC_F3 |  | 
| KC_F4 |  | 
| KC_F5 |  | 
| KC_F6 |  | 
| KC_F7 |  | 
| KC_F8 |  | 
| KC_F9 |  | 
| KC_F10 |  | 
| KC_F11 |  | 
| KC_F12 |  | 
| KC_F13 |  | 
| KC_F14 |  | 
| KC_F15 |  | 
| KC_F16 |  | 
| KC_F17 |  | 
| KC_F18 |  | 
| KC_F19 |  | 
| KC_F20 |  | 
| KC_F21 |  | 
| KC_F22 |  | 
| KC_F23 |  | 
| KC_F24 |  | 
Punctuation
| Key | Aliases | Description | 
| KC_ENTER | KC_ENT | Return (Enter) | 
| KC_ESCAPE | KC_ESC | Escape | 
| KC_BSPACE | KC_BSPC | Delete (Backspace) | 
| KC_TAB |  | Tab | 
| KC_SPACE | KC_SPC | Spacebar | 
| KC_MINUS | KC_MINS | -and_ | 
| KC_EQUAL | KC_EQL | =and+ | 
| KC_LBRACKET | KC_LBRC | [and{ | 
| KC_RBRACKET | KC_RBRC | ]and} | 
| KC_BSLASH | KC_BSLS | \and| | 
| KC_NONUS_HASH | KC_NUHS | Non-US #and~ | 
| KC_NONUS_BSLASH | KC_NUBS | Non-US \and| | 
| KC_INT1 | KC_RO | JIS \and| | 
| KC_INT2 | KC_KANA | JIS Katakana/Hiragana | 
| KC_INT3 | KC_JYEN | JIS ¥ | 
| KC_SCOLON | KC_SCLN | ;and: | 
| KC_QUOTE | KC_QUOT | 'and" | 
| KC_GRAVE | KC_GRV | `and~ | 
| KC_COMMA | KC_COMM | ,and< | 
| KC_DOT |  | .and> | 
| KC_SLASH | KC_SLSH | /and? | 
| KC_CAPSLOCK | KC_CAPS | Caps Lock | 
Modifiers
| Key | Aliases | Description | 
| KC_LCTRL | KC_LCTL | Left Control | 
| KC_LSHIFT | KC_LSFT | Left Shift | 
| KC_LALT |  | Left Alt | 
| KC_LGUI | KC_LCMD,KC_LWIN | Left GUI (Windows/Command/Meta key) | 
| KC_RCTRL | KC_RCTL | Right Control | 
| KC_RSHIFT | KC_RSFT | Right Shift | 
| KC_RALT |  | Right Alt | 
| KC_RGUI | KC_RCMD,KC_RWIN | Right GUI (Windows/Command/Meta key) | 
| KC_LOCKING_CAPS | KC_LCAP | Locking Caps Lock | 
| KC_LOCKING_NUM | KC_LNUM | Locking Num Lock | 
| KC_LOCKING_SCROLL | KC_LSCR | Locking Scroll Lock | 
| KC_INT4 | KC_HENK | JIS Henkan | 
| KC_INT5 | KC_MHEN | JIS Muhenkan | 
Commands
| Key | Aliases | Description | 
| KC_PSCREEN | KC_PSCR | Print Screen | 
| KC_SCROLLLOCK | KC_SLCK | Scroll Lock | 
| KC_PAUSE | KC_PAUS | Pause | 
| KC_INSERT | KC_INS | Insert | 
| KC_HOME |  | Home | 
| KC_PGUP |  | Page Up | 
| KC_DELETE | KC_DEL | Forward Delete | 
| KC_END |  | End | 
| KC_PGDOWN | KC_PGDN | Page Down | 
| KC_RIGHT | KC_RGHT | Right Arrow | 
| KC_LEFT |  | Left Arrow | 
| KC_DOWN |  | Down Arrow | 
| KC_UP |  | Up Arrow | 
| KC_APPLICATION | KC_APP | Application (Windows Menu Key) | 
| KC_POWER |  | Power | 
| KC_EXECUTE |  | Execute | 
| KC_HELP |  | Help | 
| KC_MENU |  | Menu | 
| KC_SELECT |  | Select | 
| KC_AGAIN |  | Again | 
| KC_UNDO |  | Undo | 
| KC_CUT |  | Cut | 
| KC_COPY |  | Copy | 
| KC_PASTE |  | Paste | 
| KC_FIND |  | Find | 
| KC_ALT_ERASE |  | Alternate Erase | 
| KC_SYSREQ |  | SysReq/Attention | 
| KC_CANCEL |  | Cancel | 
| KC_CLEAR |  | Clear | 
| KC_PRIOR |  | Prior | 
| KC_RETURN |  | Return | 
| KC_SEPARATOR |  | Separator | 
| KC_OUT |  | Out | 
| KC_OPER |  | Oper | 
| KC_CLEAR_AGAIN |  | Clear/Again | 
| KC_CRSEL |  | CrSel/Props | 
| KC_EXSEL |  | ExSel | 
Media Keys
These keycodes are not part of the Keyboard/Keypad usage page. The SYSTEM_ keycodes are found in the Generic Desktop page, and the rest are located in the Consumer page.
Windows and macOS use different keycodes for "next track" and "previous track". Make sure you choose the keycode that corresponds to your OS.
| Key | Aliases | Description | 
| KC_SYSTEM_POWER | KC_PWR | System Power Down | 
| KC_SYSTEM_SLEEP | KC_SLEP | System Sleep | 
| KC_SYSTEM_WAKE | KC_WAKE | System Wake | 
| KC_MAIL | KC_MAIL |  | 
| KC_CALCULATOR | KC_CALC |  | 
| KC_MY_COMPUTER | KC_MYCM |  | 
| KC_WWW_SEARCH | KC_WSCH |  | 
| KC_WWW_HOME | KC_WHOM |  | 
| KC_WWW_BACK | KC_WBAK |  | 
| KC_WWW_FORWARD | KC_WFWD |  | 
| KC_WWW_STOP | KC_WSTP |  | 
| KC_WWW_REFRESH | KC_WREF |  | 
| KC_STOP |  | Stop | 
| KC_WWW_FAVORITES | KC_WFAV |  | 
| KC__MUTE |  | Mute (macOS) | 
| KC__VOLUP |  | Volume Up (macOS) | 
| KC__VOLDOWN |  | Volume Down (macOS) | 
| KC_AUDIO_MUTE | KC_MUTE | Mute (Windows/macOS/Linux) | 
| KC_AUDIO_VOL_UP | KC_VOLU | Volume Up (Windows/macOS/Linux) | 
| KC_AUDIO_VOL_DOWN | KC_VOLD | Volume Down (Windows/macOS/Linux) | 
| KC_MEDIA_NEXT_TRACK | KC_MNXT | Next Track (Windows) | 
| KC_MEDIA_PREV_TRACK | KC_MPRV | Previous Track (Windows) | 
| KC_MEDIA_FAST_FORWARD | KC_MFFD | Next Track (macOS) | 
| KC_MEDIA_REWIND | KC_MRWD | Previous Track (macOS) | 
| KC_MEDIA_STOP | KC_MSTP | Stop Track | 
| KC_MEDIA_PLAY_PAUSE | KC_MPLY | Play/Pause Track | 
| KC_MEDIA_SELECT | KC_MSEL |  | 
Number Pad
| Key | Aliases | Description | 
| KC_NUMLOCK | KC_NLCK | Keypad Num Lock and Clear | 
| KC_KP_SLASH | KC_PSLS | Keypad / | 
| KC_KP_ASTERISK | KC_PAST | Keypad * | 
| KC_KP_MINUS | KC_PMNS | Keypad - | 
| KC_KP_PLUS | KC_PPLS | Keypad + | 
| KC_KP_ENTER | KC_PENT | Keypad Enter | 
| KC_KP_1 | KC_P1 | Keypad 1and End | 
| KC_KP_2 | KC_P2 | Keypad 2and Down Arrow | 
| KC_KP_3 | KC_P3 | Keypad 3and Page Down | 
| KC_KP_4 | KC_P4 | Keypad 4and Left Arrow | 
| KC_KP_5 | KC_P5 | Keypad 5 | 
| KC_KP_6 | KC_P6 | Keypad 6and Right Arrow | 
| KC_KP_7 | KC_P7 | Keypad 7and Home | 
| KC_KP_8 | KC_P8 | Keypad 8and Up Arrow | 
| KC_KP_9 | KC_P9 | Keypad 9and Page Up | 
| KC_KP_0 | KC_P0 | Keypad 0and Insert | 
| KC_KP_DOT | KC_PDOT | Keypad .and Delete | 
| KC_KP_EQUAL | KC_PEQL | Keypad = | 
| KC_KP_COMMA | KC_PCMM | Keypad , | 
| KC_KP_EQUAL_AS400 |  | Keypad =on AS/400 keyboards | 
Special Keys
In addition to these, keycodes in the range of 0xA5-DF are reserved for internal use by TMK.
| Key | Aliases | Description | 
| KC_NO |  | Ignore this key (NOOP) | 
| KC_TRANSPARENT | KC_TRNS | Use the next lowest non-transparent key |