Every touch carries a physical signature: the size of your fingertip, the pressure you apply,
and the angle of contact. The Touch API exposes all of this — radius, force, rotation —
without any permission prompt.
The physical size, pressure, and angle of your finger on glass is biometrically unique.
Combined with typing rhythm, it identifies you to authentication systems — without any password.
Mobile banking apps already use touch biometrics as a continuous background authentication layer.
0touches
—avg radius px
—force support
touch fingerprint canvas
touch anywhere
force = 0 on all touches — this device does not expose pressure data
no touches recorded yet
▶ the biometrics of a touch
The browser's TouchEvent API exposes far more than just X/Y coordinates. Each touch point includes:
radiusX / radiusY — the elliptical contact area of your fingertip in CSS pixels
rotationAngle — the angle of the ellipse (how tilted your finger is)
force — pressure from 0.0 (lightest) to 1.0 (maximum), on supported hardware
Your fingertip size is determined by the width of your distal phalanx — typically 8–20mm. This varies by person and is stable over time. Combined with how hard you tap and your natural tilt angle, it forms a biometric signature that is independent of which finger you use.
Most Android devices do not expose force data (it returns 0). Apple devices with 3D Touch (iPhone 6s–11) or Haptic Touch expose partial force data. The radius and rotation data are available on almost all touch screens.
This data is accessible to any webpage you visit on a touch device — no permission required.