Remap any key for left-handed gaming. Low latency, native Rust engine.
- WASD → IJKL (or arrows, numpad) for left-hand movement
- Map any key to any other:
W→I,Q→U,Caps→Ctrl,Win→Disabled - Add-mapping validation: duplicate sources and self-maps are blocked inline
- Accent Color themes: 10 presets + custom picker (Settings → Appearance)
- Profile Import/Export to
.jsonwith merge or replace modes - Interface sounds: distinct chimes for activate vs pause (Settings → General)
- Tabbed Settings: General, Appearance, Input, Profiles, About
- Works in any game (low-level hook)
- Very low latency native Rust engine (verify live in Settings → About)
- Clean dark UI
| Add mapping | Delete mapping |
|---|---|
 |
 |
| General | Appearance |
|---|---|
 |
 |
| Input | Profiles |
|---|---|
 |
 |
git clone https://github.com/EtherealDevv/Lefty
cd Lefty
# Run
.\dist\Lefty.exe
# Or install
.\dist\Lefty_1.3.0_x64-setup.exeRun as Administrator for games that run elevated.
| Profile | Mapping |
|---|---|
| Sycho — OÑLK | O→W, K→A, L→S, Ñ→D + mirrored |
| Left-handed IJKL | W→I, A→J, S→K, D→L |
| Arrow Keys | W→UP, A→LEFT... |
| Custom | Empty, make your own |
| Disabled | No remap |
- Pick a profile on the left
- Add or Capture a mapping (
W→I, duplicates rejected) - Activate
- Play (activate before launching the game)
- Pause to restore,
F6to toggle, close to tray - Back up via Settings → Profiles → Export, restore via Import
| Method | Latency |
|---|---|
| Registry | 0ms (reboot, not dynamic) |
| Lefty | low latency* |
*Verify it yourself live in the app: Settings → About → Engine latency. | AutoHotkey | 5-15ms |
Lefty/
├── core/ # keys, profiles
├── engine/ # remapper (Rust + Python fallback)
├── engine_native/ # Rust engine
├── tauri-app/ # Rust + React UI
└── dist/ # Lefty.exe + installers
- Not working in game: Run as Admin. Some anti-cheats block hooks → use Interception.
- Stuck key: Pause and resume.
- High delay: Close other hooks (AutoHotkey).
- Remapping architecture inspired by Microsoft PowerToys Keyboard Manager (low-level hook +
SendInputdesign, Task Scheduler autostart pattern) — reimplemented from scratch in Rust with a zero-GC hot path, batched injection and live latency telemetry for lower, measurable latency.
MIT — Made for left-handed gamers.