What Is Gamepad Fingerprinting? – Definition and How It Works
Learn what the Gamepad API exposes, why an empty list is normal, and where this niche signal actually matters.
Gamepad fingerprinting reads connected game controllers via the Gamepad API. It is one of the narrowest fingerprinting surfaces, and its value is almost entirely in the rare case where a controller is present.
1. The API
const pads = navigator.getGamepads();
// each connected pad: {id, index, mapping, axes, buttons, connected, timestamp}
id is the high-entropy field — a vendor and product string naming the specific controller model, sometimes with vendor and product identifiers.
2. Why Empty Is Unremarkable
Most people have no controller connected to the browser at any given moment, so an empty array is the overwhelmingly common result.
That makes this surface unusual among fingerprinting signals: the absence of data is the normal case, so a headless browser reporting no gamepads looks exactly like almost every real visitor.
Contrast with media devices, where an empty list is abnormal and therefore revealing.
3. Where It Does Carry Signal
Three cases:
A controller is present. Then the id string is highly identifying — a specific model, often with identifiers — and combined with other signals it narrows a device considerably.
The API is missing entirely. navigator.getGamepads absent on a browser claiming a version that has it is a contradiction, and that is the automation-relevant reading.
The API throws or behaves oddly, which suggests a patched or unusual environment.
4. A Permission and Gesture Nuance
Browsers have progressively restricted gamepad access: in some, controllers are only exposed after a user gesture involving the device, precisely to prevent silent enumeration.
The consequence is that a page cannot reliably enumerate controllers on load, which further weakens the surface — and means a session that does report controllers without any interaction is behaving unusually.
5. Do Not Fabricate Gamepads
A tempting but counterproductive idea. Reporting a connected controller:
- Moves you from the common case (none) to a rare one.
- Requires the
idstring, axes count, button count, and mapping to be mutually plausible. - Requires
timestampto update coherently if the page polls. - Involves overriding a native method, which hook detection catches.
Every one of those is a new way to be inconsistent, in exchange for no benefit. The honest empty array is both simpler and less distinctive.
6. Where It Realistically Appears
Gamepad enumeration shows up in fingerprinting libraries as one entry among dozens, contributing a small amount of entropy for the minority of visitors who have a controller. It is not a signal any serious detection relies on alone.
Its more interesting role is as a completeness check on a stealth configuration: a setup that patches navigator properties, plugins, and WebGL but leaves getGamepads throwing or missing is inconsistent, and that inconsistency is the finding rather than the gamepad data itself.
7. Practical Guidance
- Leave it alone. An empty array is the normal, unremarkable result.
- Ensure the API exists if the claimed browser version provides it.
- Do not fabricate controllers — it only adds contradictions.
- Treat it as very low priority next to address reputation, TLS fingerprint, and rendering signals.
8. Summary
Gamepad fingerprinting enumerates connected controllers, where the id string identifies a specific model, but an empty list is the normal case for almost every real visitor — so reporting none is unremarkable.
Its automation relevance is the reverse of most surfaces: the signal is a missing or broken API on a browser that should have it, not the absence of controllers, and fabricating gamepads only creates contradictions for no gain.