DeviceCheck’s Keyboard Tester Knows What Your Keyboard Is Doing

Field notes

The tester offers several keyboard layouts, including ANSI, ISO, 60% compact, and tenkeyless configurations, then records event-level details such as physical code, location, modifiers, repeat state, and keyCode. A separate rollover test counts simultaneously reported keys, while the timing section flags same-key presses arriving within 40 milliseconds as possible chatter. The page distinguishes these browser-observable behaviors from switch latency, which it says cannot be measured reliably here.