About this gamepad tester
Plug in a controller or pair it over Bluetooth, then press a button: browsers only reveal a gamepad after a press. Every button lights up with its pressure (triggers are analog, 0 to 1), labelled for Xbox, PlayStation or Nintendo layouts. Each stick shows its exact X and Y. Leave the sticks alone to check for drift: a resting value above a few percent means the stick is not returning to centre. Rotate each stick slowly around its edge to measure circularity, and use the rumble buttons to test both vibration motors.