Skip to content

Logitech G-Keys

The G-keys on a Logitech keyboard, and the extra buttons on a Logitech mouse, as a device row you can map and put in macros.

A G-key is not a keyboard key. It sends nothing until you program it in Logitech's own software, and the usual way to make one useful elsewhere is to have it type some real key, which burns a keycode, fires in every program on the machine, and puts two remappers in series.

PadForge reads the G-keys directly through Logitech's G-key SDK instead. They arrive as their own device row, bind through the same grid every other device uses, and never reach any other program.

Turning it on

Open Settings, find the Input Engine card, and tick Read Logitech G-Keys. It is off by default, because turning it on loads a third-party library and opens a session with the Logitech software.

A Logitech G-Keys row then appears on the Devices page.

What you need

Logitech Gaming Software 8.55 or later, running. The SDK ships with it.

One more step matters, and it happens in Logitech's software rather than in PadForge. Logitech Gaming Software lets you nominate one persistent profile, which keeps receiving G-keys no matter which program is in front. Make PadForge that profile. Without it the SDK only feeds whichever program has focus, so your G-keys work in PadForge's own window and nowhere else.

This is unrelated to PadForge's own profiles, which are a different thing that lives on the Profiles page.

Reading the status line

Under the checkbox is a line saying exactly which of seven situations the machine is in, so a quiet G-key is never a mystery.

Status What to do
No Logitech G-key SDK on this machine. It installs with Logitech Gaming Software 8.55 or later. Install Logitech Gaming Software.
The G-key SDK is registered but its file is gone. Reinstall Logitech Gaming Software. Reinstall it.
Found the G-key SDK and could not load it. Usually an architecture mismatch or a damaged install.
That library is not the G-key SDK this expects. Something else is registered under the SDK's key.
The G-key SDK refused to start. Logitech Gaming Software is usually not running. Start Logitech Gaming Software.
Connected, no key seen yet. In Logitech Gaming Software, make PadForge the persistent profile. Do that, then press a G-key.
Running, {0} key events Working, with the count in place of {0}. It rises as you press keys.

The line is empty while the feature is off.

What the row exposes

102 buttons, in a fixed layout:

  • G1 through G29, in each of M1, M2 and M3. 87 buttons. One physical G-key carries three bindings, which is what the M-state keys are for. The row names them G5 (M2) and so on.
  • Mouse buttons 6 through 20. 15 buttons, for the extra buttons on a Logitech mouse.

Every one of the 102 is listed even on a keyboard with six G-keys, because the SDK has no way to report how many a given device has. Finding the right entry is what the Record button is for: press it, press the key, and it binds.

While the SDK is not running, the row retires and rebuilds every five seconds to retry it, so it can blink out of the Devices list between attempts.

The layout is fixed rather than derived from the attached hardware, so a saved mapping keeps pointing at the same key when you plug in a different Logitech keyboard.

Mapping it

The row binds anywhere a button does, including macros and menus. An (Any Device) source never reads it, so pick the G-Keys row by name.

A tap can begin and end between two of PadForge's polls, so a press is held asserted briefly after it arrives. A macro sees the edge either way.

Limitations

This runs against Logitech's own library, and nothing here has been exercised against real Logitech hardware or software. The wire format comes from LogitechGkeyLib.h in the SDK and was cross-checked against Mumble's long-running implementation, so the decoding is grounded, but the library loading and calling back on a live machine is unverified.

G HUB is not Logitech Gaming Software. The G-key SDK ships with Logitech Gaming Software, and a machine running only G HUB may not register it.

Last updated for PadForge 4.5.1.