ChatterFix

Stop your keyboard from typing double. A small, free tool that fixes keyboard chatter, which is when a worn or dirty key registers two presses from a single tap. Think "hello" coming out as "helllo", or space bar double-spacing.

Download for macOS or Windows at chatterfix.app

Free forever, source available, no ads, no account, no tracking.

What is keyboard chatter?

As a key switch ages or collects dust, one press can electrically bounce and report twice. ChatterFix watches your keystrokes and ignores that bogus second press. If a key fires again within a few milliseconds of releasing the same key, it counts as a bounce and gets dropped. Real typing leaves a much bigger gap, even fast double letters like "ll", so normal typing is not affected.

A few things worth knowing:

• It adds no delay. Every real keystroke passes through instantly. Nothing is buffered or held back.
• Holding a key still works normally, and it only ever compares a key against itself, so typing fast across different keys is fine.
• It never records what you type. ChatterFix looks only at timing, meaning which key and how long since that key was last released, and it keeps none of it. The full source is in this repo if you want to check.

Download

Get the latest build from chatterfix.app or the Releases page:

• macOS: universal .dmg that runs on both Apple Silicon and Intel Macs, macOS 13 or newer.
• Windows: .exe for Windows 10 and 11. No installer, nothing else to set up.

First launch

The downloads are not signed with a paid certificate, so both systems show a one-time warning. Neither means anything is wrong with the app.

macOS. Drag ChatterFix into Applications, then right-click it and choose Open. The warning appears again but now has an Open button; click it.

A plain double-click will not work the first time, and neither will Launchpad. Both report "ChatterFix can't be opened because Apple cannot check it for malicious software", add "This software needs to be updated. Contact the developer for more information", and offer only Show in Finder and OK, neither of which opens anything. There is nothing to update. That is simply what macOS says about any app without a paid Apple certificate, and right-click then Open is the only route past it. Once opened that way the app launches normally from then on, Launchpad and Dock included.

Windows. SmartScreen shows a blue "Windows protected your PC" box. Click More info, then Run anyway. The button only appears after More info, which is easy to miss.

The first launch on macOS then asks for the Accessibility permission, which it needs to watch for chatter.

Both versions turn on Start at Login for themselves the first time they run, so chatter stays fixed after a reboot without anyone having to think about it. It is set once, not enforced: switch it off and it stays off. On macOS the entry is visible under System Settings, then General, then Login Items, and on Windows under the Run key for the current user only.

How to use it

ChatterFix sits in your menu bar (macOS) or system tray (Windows) as a small keyboard icon. Click it to:

• See how many double-presses it has blocked and which keys are chattering.
• Change the sensitivity, which is how close together two presses must be to count as chatter. Standard (50 ms) is a good starting point. If doubles still get through, move one step stronger. If a genuine fast double letter gets eaten, move one step gentler.
• Pause filtering, or turn Start at Login off (it starts on).

Building from source

• macOS: see mac/. Run ./build_app.sh (needs the Xcode command-line tools). More detail in mac/README.md.
• Windows: see windows/. Run build.cmd, which uses the C# compiler already built into Windows. More detail in windows/README.md.

Limitations

• Modifier keys (Shift, Cmd or Win, Ctrl, Alt or Option) travel a different event path and are not filtered. Chatter on those is rare.
• Games with kernel-level anti-cheat and secure password fields read input below where ChatterFix sits, so filtering does not apply there.

License

MIT with the Commons Clause. Free to use, change, fork, and share, including at work and inside a company. The one thing you cannot do is sell it, or sell a product or service whose value comes substantially from it.

Note that this is source available rather than open source in the OSI sense, because the no-selling condition is a restriction on use.