Predictive Key Lights

Your keyboard shows you what you're about to type. After every key press, the key you're most likely to press next lights up green, the second most likely yellow, and the third red. Every other key goes dark. It works in any app on Windows, and it knows whether you're writing English, Python, JavaScript or a PowerShell, cmd or bash command.

Type t and H lights up (then O, R). Type th and you get E, A, I. After the it's Space.

Modes

Python in VS Code: after os.list comes D (listdir)	PowerShell in Windows Terminal: -fi → L (-Filter)

Mode	Predicts from	Picked automatically when you type in
English	59,000-word frequency list (wordfreq)	anything else
Python	the Python standard library	an editor or IDE with a .py file in its title
JavaScript / TypeScript	Node.js and npm sources	.js .mjs .cjs .jsx .ts .tsx
PowerShell	Windows PowerShell modules and common commands	powershell, pwsh, PowerShell tabs in Windows Terminal (and unknown terminals)
Command Prompt	.bat/.cmd files and common commands	cmd.exe, Command Prompt tabs
Bash / Git Bash / WSL	Git for Windows shell scripts and common commands	Git Bash (mintty), wsl, bash, tabs titled MINGW64, user@host:~ ...

Auto (the default) follows the window you're typing in. Pick a mode in the drop-down to fix it. In code and terminal modes Enter can light up too, and pressing it carries the context to the next line.

It learns how you type

English learns your words and which word you type after which. Code and terminal modes learn your names (identifiers, commands) and your character patterns. What you type is mixed in by confidence, so a word or pattern you've used once or twice already shows up. Type "hi claude" once and hi lights C next time.

The Learning card counts what each mode has picked up. It stays in memory unless Remember between sessions is on. Then it's saved (every minute and on close) to %APPDATA%\PredictiveKeyLights\learned.json, on your PC only. Forget everything learned wipes it.

Passwords and private mode

• Password fields are skipped automatically. This covers browsers, most apps, Windows sign-in prompts and classic password boxes (it uses Windows UI Automation). Keystrokes there aren't recorded or learned, the context around them is dropped, and every key goes dark so the lights give nothing away.
• Private mode, Ctrl+Alt+P, does the same by hand, from anywhere, for prompts Windows can't see as password fields: sudo, ssh, Read-Host -AsSecureString, a password typed into a chat... Press it before typing and again after. A rising beep means private, a falling beep means back to normal. The hotkey itself is never passed on to the app you're in. Change it with private_hotkey in the settings, e.g. "ctrl+shift+f12".

Show typed text (on by default) shows what you typed in the window. Turn it off if people can see your screen.

Keyboards

Brand	How	You need
Logitech G (G610 tested)	G HUB LED SDK	G HUB running. White-only boards (G610, G710) show the 3 guesses as bright, medium and dim
Razer (BlackWidow, Huntsman, Ornata, ...)	Chroma SDK	Razer Synapse with Chroma Connect
SteelSeries (Apex, ...)	GameSense	SteelSeries GG (Engine) running
Keychron (Q, V, K Max/Pro/HE, ...)	OpenRGB	OpenRGB 1.0+ with the SDK Server started, Keychron firmware 1.1.1+, USB cable (not Bluetooth / 2.4 GHz)
Keyboardio Model 100	Focus serial	the MusicLEDs firmware from rgb-music-visualizer; Chrysalis closed
Corsair, HyperX, ASUS, Wooting, other QMK/VialRGB	OpenRGB	OpenRGB with the SDK Server started (and the vendor app closed)

Keyboards are found automatically (Rescan checks again). When a keyboard is plugged in but can't be lit yet, it's still listed, marked needs setup, with what to do. For example, start Synapse, or connect the Keychron with a cable.

Notes:

• Only the Logitech G610 has been tested with this app on real hardware (the Model 100 driver is the one used in rgb-music-visualizer). The Razer, SteelSeries and OpenRGB drivers are tested against simulated services. Reports welcome.
• Key positions assume a US layout (and the default QWERTY layer on the Model 100).
• Don't let two programs drive the same keyboard, for example a Razer board through both Synapse and OpenRGB, or this together with rgb-music-visualizer.
• Keychron boards on older firmware, or connected wirelessly, can't set individual keys from a PC.

Install

Needs Windows 10/11 and Python 3.12.

git clone https://github.com/vantfindthe/predictive-key-lights
cd predictive-key-lights
setup.bat

Then start it with KeyLights.bat. The models are included; no internet connection is needed after setup.

Settings

%APPDATA%\PredictiveKeyLights\settings.json:

Setting	Default
colors	green, yellow, red	RGB for the 1st, 2nd and 3rd guess
white_levels	[255, 80, 18]	brightness per guess on white-only keyboards
private_hotkey	"ctrl+alt+p"	modifiers (ctrl alt shift win) + a letter, digit, f1-f24, pause, scrolllock, insert or space
hotkey_sound	true	beep when private mode switches
idle_release_s	0	hand the keyboards their own lighting back after this many idle seconds (0 = never)

Training on your own code or shell history

.venv\Scripts\python tools\build_modes.py python --extra D:\src\my-project
.venv\Scripts\python tools\build_modes.py powershell bash --history
.venv\Scripts\python tools\build_modes.py rust --new "Rust" .rs D:\src\some-rust-repo

• --extra adds your own code to a mode.
• --history trains the terminal modes on your PowerShell or bash command history, which is the best data for them. The model then holds fragments of that history, so don't share the .json.gz it writes.
• --new adds a language. Auto then picks it up by file extension.

Restart the app after rebuilding.

How it works

Path	What
app/app.py	window (CustomTkinter)
app/engine.py	keystrokes -> context -> predictions -> frames; one sender thread for all keyboards
app/hook.py	system-wide keyboard hook (read-only, except the private-mode hotkey)
app/predict.py	English word model, code/terminal character n-gram models, learning
app/modes.py	Auto mode: which mode fits the focused window
app/secure.py	password-field detection (UI Automation + Win32)
app/devices/	one module per keyboard backend, plus connected-keyboard detection
tools/build_modes.py, tools/seeds/	trains the code and terminal models
tools/build_wordlist.py	regenerates the English word list
tools/screenshots.py	renders the screenshots above (scripted, no real typing)

English prediction: every word that starts with what you've typed votes for its next letter, weighted by how common it is. A finished word votes for space and punctuation. A letter-trigram model covers names and typos. Code and terminal modes use a 7-character n-gram model (trained with indentation stripped, since editors insert it) blended with completion from the mode's vocabulary.

License

GPL-3.0. See LICENSE. The keyboard drivers come from rgb-music-visualizer.