Live view versus health check
The overview, buttons, sticks and triggers tabs are live viewers. They exist so you can confirm the browser sees the pad, chase a sticky bumper, or watch analog travel. They do not pass or fail anything. A stick sitting at +0.08 while you hold the controller is not a diagnosis.
Run health check when you want a verdict. The guided flow gates every hands-off sample behind a countdown, then walks range and circularity, snapback, buttons, triggers, and rumble. You can stop after centre if all you needed was a stick drift test.
What “good” looks like for a used pad
A healthy used controller is quiet at rest, reaches at least seven of eight outer sectors on each stick, returns from a flick without a large opposite-direction spike, and reports every required face button, bumper, stick click and D-pad direction. Analog triggers should reach 90% at least once. Circularity under 5% error is excellent; over 15% usually means the gimbal is oval or the rest used for the math is wrong — which is why we subtract the measured rest first.
If you play FPS titles, read the snapback number even when the overall score is high. A pad can rest cleanly and still overshoot on release, which feels like a recoil twitch. That is a different failure mode from drift and it is called out on the results card.
When the browser is the limit
The Gamepad API is not a USB analyzer. It will not show DualSense adaptive-trigger resistance, Xbox Elite paddles, gyro, or a true 1000 Hz wired poll. CTRLCHK labels those gaps instead of approximating them. Browser-observed update rate is printed as such on the polling rate test. Rumble uses vibrationActuator and is skipped without penalty on browsers that omit it.
Platform-specific names help when you are staring at a DualSense or an Xbox pad: use the PS5 controller test or the Xbox controller test if you want Cross/Circle or A/B labels in the checklist.