Probe your mouse, keyboard, screen, gamepad & touch. All 8 tools below run locally in your browser — nothing is uploaded.
Hardware fails gradually and ambiguously. A mouse switch starts registering one click as two, a key occasionally repeats itself, a monitor develops a pixel you only notice on a particular background. The hard part is confirming the fault is real before deciding to replace anything.
These tools measure exactly that: the interval between click events so a double-fire is visible as a number, repeated key events that arrive too close together to be human, every key held at once to check rollover, and full-screen colour fields for finding dead or stuck pixels.
The Double-Click Tester times the gap between clicks. Anything under about 50ms that you did not intend is a switch bouncing — it is a hardware fault, and a consistent pattern of it is grounds for a warranty claim.
It is how many keys your keyboard can report simultaneously. Hold as many as you can in the Key Rollover tester: membrane boards typically stop at six, mechanical boards with full NKRO report every key you press.
It can help you find one. The tool fills the screen with solid colours in turn — a dead pixel stays black on every field, a stuck one stays the same colour on all of them.