Test any controller in your browser - buttons, triggers and joysticks, live. Great for checking stick drift. Free, no download.
Plug in or connect your controller and press any button - it appears instantly. Buttons light up when pressed and the sticks show live X/Y values so you can spot drift.
Leave the sticks untouched and watch the axis values. If they do not rest near 0.00, or drift on their own, your stick has drift.