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keys were held down for a measurable moment

Check id key-press-dwell-duration

What an ordinary browser yields

A shortest key hold of tens of milliseconds. N/A when IME composition was used, when no keydown/keyup pair was measurable (paste, autofill and dictation produce none), or on a coarsened clock (severity: warn).

What a detector infers

The keyboard twin of the press-dwell row, and it is deliberately separate because the two fail independently - which SeleniumBase 4.51.5 demonstrates precisely. That release FIXED the key sequence: it now emits rawKeyDown, char and keyUp with key, code and the virtual key codes populated, so every structural keyboard row on this page passes. Measured over a 49-character phrase on Chrome 150, the timing did not change: keydown-to-keyup was 1.0ms under send_keys and 1.4ms under press_keys - which is its explicitly human-paced mode - against 96ms for a hand-driven control. press_keys spaces the CHARACTERS convincingly, roughly 50ms apart, and still releases each key 1.4ms after pressing it. That is the whole point of measuring the hold separately from the rhythm: a driver can fix the gaps between keys, and fix the event sequence, and still be releasing keys faster than any finger. Auto-repeat keydowns are excluded from pairing, because a held key emits many keydowns and one keyup and pairing across that would measure the wrong interval entirely.

How to resolve it

Dispatch keyUp on a later tick than rawKeyDown rather than immediately after it. Typing helpers that space out characters commonly still release each key instantly, which fixes the rhythm between keys while leaving the hold itself impossible.

Nearby checks in Automation surface

See all 37 checks in Automation surface
Who builds this test

Clearcote is a browser built for fingerprint coherence

It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.

This audit takes no position on how Clearcote scores on Automation surface checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.

See the other checks in Automation surface — the family key-press-dwell-duration belongs to.