KeyResolve

Snap Tap / SOCD-style keyboard input handling for Linux (Wayland & X11)

KeyResolve is a low-latency userspace input interceptor for Linux that enforces mutually exclusive movement keys (e.g. A/D, W/S) using a last-pressed-wins policy.

It works by intercepting raw keyboard events via evdev, applying deterministic key logic, and re-emitting corrected events through a virtual keyboard (uinput). This approach works reliably on Wayland, X11, and in games that use raw input.

Features

• ✅ Last-pressed-wins logic for movement keys
• ✅ Guarantees no simultaneous A+D and W+S
• ✅ Works on Wayland and X11
• ✅ Game-compatible (raw input / evdev level)
• ✅ Written in Rust
• ✅ No kernel modules
• ✅ No compositor plugins
• ✅ Clean Ctrl-C shutdown (no stuck keys)

Installation

Download from GitHub Releases

Navigate to the Releases and download the binary for your architecture.

Build from source

git clone https://github.com/Antosser/KeyResolve.git
cd KeyResolve
cargo build --release

The binary will be located at:

target/release/KeyResolve

Permissions & udev setup (required unless root)

KeyResolve needs access to:

• /dev/input/event* (read)
• /dev/uinput (write)

Create a udev rule

Create /etc/udev/rules.d/99-input.rules:

KERNEL=="event*", SUBSYSTEM=="input", GROUP="input", MODE="660"
KERNEL=="uinput", GROUP="input", MODE="660"

Reload rules:

sudo udevadm control --reload-rules
sudo udevadm trigger

Add your user to the input group

sudo usermod -aG input $USER

Then log out or reboot.

Usage

Run the program:

./KeyResolve

You will be prompted to select which keyboard to grab.

Once running:

• Pressing A releases D
• Pressing D releases A
• Pressing W releases S
• Pressing S releases W
• When the last pressed key is released, the previous still-held key (if any) is restored

Exit cleanly with Ctrl+C.

Safety notes

• The selected keyboard is exclusively grabbed

• If the program crashes, input from that keyboard may temporarily stop

• Always test from:

  • a TTY, or
  • an SSH session, or
  • with a second keyboard available

The program handles Ctrl-C correctly and releases all keys on exit.

Supported platforms

• ✅ Linux
• ✅ Wayland
• ✅ X11
• ❌ Windows
• ❌ macOS

Why not X11 key remapping?

• X11 remapping does not work reliably on Wayland
• Many games bypass X11 entirely
• KeyResolve operates at the evdev level, where games actually read input

Contributing

Contributions are welcome!

Good areas to help with:

• Generalizing key-pair handling
• Adding configuration support
• Improving documentation
• Testing on different keyboards
• Packaging (Arch / Nix / etc.)

Development setup

cargo check
cargo clippy
cargo fmt

Please keep changes:

• Idiomatic Rust
• Well-commented
• Minimal unsafe code (preferably none)

License

GPL-3.0 License See LICENSE for details.