The Web Gamepad API gives a page access to controller objects that a browser chooses to expose. It is widely useful, but availability does not guarantee identical device names, button ordering, axis ordering or feature support across platforms.
User activation and exposure
Browsers may wait for a gamepad button press before exposing a connected device. This reduces passive fingerprinting and means a controller can be physically connected while navigator.getGamepads() initially returns empty entries. Keymap Labs prompts the user to press a button and listens for connection events while continuing to inspect the current list.
Several browser device features require a secure connection. Use https://keymap.io, keep the browser current and avoid copied or embedded versions of the page when comparing results.
Standard and generic mappings
A gamepad object can declare the standard mapping, which gives common positions for face buttons, shoulders, triggers, sticks and directional buttons. Generic devices may provide an empty mapping and expose raw arrays in a device-specific order.
Keymap Labs always shows raw button indices and axis values. This keeps the tool useful even when a controller does not match the familiar diagram. It does not rename a generic input with unjustified certainty.
Analog triggers may appear as buttons with fractional values, separate axes or digital buttons depending on the stack. Additional features such as touchpads, gyro, battery state, LEDs and haptics are not consistently available through the core mapping and are outside the standard diagnostic scope.
Connection and index behavior
Gamepads receive an index within the browser session. Disconnecting and reconnecting can change which entry is active. The live lab selects an available device and responds to connection changes; use the device selector when several controllers are exposed.
Wireless mode can expose a different identifier or feature set from USB mode. That difference should be recorded during troubleshooting. A browser-visible identifier may also be generic for privacy or driver reasons.
Validation matrix
A serious compatibility comparison needs physical devices across operating systems and browser engines. Keymap Labs uses the standard API and handles missing buttons or axes defensively, but an online test cannot emulate every controller driver.
A useful comparison record includes:
- Operating system and version
- Browser engine and version
- Controller model and firmware
- Wired, Bluetooth or proprietary receiver
- Reported ID, mapping, axes and button counts
- Trigger representation and stick order
- Connect, reconnect and focus behavior
Results should be treated as dated observations, not a timeless “works everywhere” badge. Browser and operating-system updates can change mappings over time.
Interpreting an empty result
No controller in the page can mean no device, no user activation, a browser limitation, a competing application, a driver layer or a connection problem. The gamepad detection guide walks through those layers in a controlled order.
If the device appears but a visual label is wrong, raw index changes still confirm that an input reached the browser. If axes do not return to center, the Stick Drift Test adds a timed sample, but that result remains bound to the current mapping and calibration.
Compatibility promise
Keymap Labs supports modern browsers that expose the Gamepad API and provides an explicit fallback state when none is available. It does not require an account, browser extension or driver. It cannot guarantee advanced controller features or universal labels.
That promise is intentionally precise. Users receive a working raw diagnostic where the platform allows it and a useful explanation where it does not.