v149 · gamepad · origin trial · experimental

Gamepad Event-Driven Input API

An extension to the Gamepad API that replaces polling (navigator.getGamepads()) with a rawgamepadinputchange event, firing synchronously on every hardware update for lower-latency, lower-CPU gamepad input.

Origin trial The Gamepad Event-Driven Input API is in origin trial in Chrome 149. The event name and interface shape may still change before it ships by default. Check the ChromeStatus entry and the explainer for the current state before shipping production code.

at a glance

Status in Chrome 149	Origin trial (experimental)
Flag	None when origin trial token is present
Spec	w3c.github.io/gamepad (extension to existing Gamepad spec)
Standards position (Firefox)	No signal
Standards position (Safari)	No signal
Blink component	Blink>Input>Gamepad
ChromeStatus	5989275208253440 — Gamepad Event-Driven Input API

Source: chromestatus.com/feature/5989275208253440

why it exists

The existing Gamepad API is polling-only: an application must call navigator.getGamepads() inside a requestAnimationFrame loop to read gamepad state. This introduces up to one frame of latency (16 ms at 60 Hz) and wastes CPU cycles even when no button is pressed. High-frequency controllers (e.g. 250 Hz gaming pads) can report 4 samples per frame that the polling model silently discards.

The event-driven model fires a rawgamepadinputchange event on window every time the hardware sends new data, regardless of the frame rate. Games and accessibility tools that need tight timing — fighting games, rhythm games, assistive devices — benefit immediately.

Source: chromestatus feature summary

shape of the API

Event	Target	Fires when
`rawgamepadinputchange`	`window`	New input data arrives from any connected gamepad

Event property	Type	Description
`event.gamepad`	`Gamepad`	Snapshot of the gamepad state at the moment of the hardware report
`event.timestamp`	`DOMHighResTimeStamp`	Time of the hardware report, not the render frame

The existing gamepadconnected / gamepaddisconnected events and navigator.getGamepads() remain available and unchanged.

Source: W3C Gamepad spec; chromestatus summary

example

// Event-driven: fires at hardware report rate, not frame rate
window.addEventListener('rawgamepadinputchange', (event) => {
  const pad = event.gamepad;

  // Read axes (e.g. left stick)
  const [lx, ly] = pad.axes;
  moveCharacter(lx, ly);

  // Read buttons
  if (pad.buttons[0].pressed) {
    jump();
  }
});

// Polling still works and is unaffected
function gameLoop() {
  const pads = navigator.getGamepads();
  for (const pad of pads) {
    if (pad) renderHUD(pad);
  }
  requestAnimationFrame(gameLoop);
}

Pattern from W3C Gamepad spec

browser support