Pretty sure we mean < 1ms rather than actually instantaneous.

Its like tic tacs saying they are 0 calories because they got the per serving size down low enough to round to 0.

Looks more like 500ms?

Unfortunately this approach doesn't feel that great down here in Australia, definitely a function of latency.

I think you could get a lot closer by framing this as an optimization problem, where you use the full alphabet dictionary, but add a residual prediction which aims to cover as much of the remaining domain name tree as possible weighted by popularity. This tree could then be pre-baked and stored with the same system. This would probably get you p99 0ms even in Australia.

its pretty clever but what happns when someone pastes a domain or uses IME or voice input? the api being that fast is still impressive.

Autocomplete aside, this is a pretty nifty tool.

KeyDown events don’t work great for mobile, though.

Clever but that’s not how we measure latency.

When it comes to UX, perceived latency is king.

The perceived latency starts from keydown, not keyup. Redefining latency to start at keyup reduces measured latency, not perceived latency, and delaying the visual display to keyup makes perceived latency strictly worse, not better. Even sticking with the keyup definition, just displaying the result as soon as it is available gives the possibility of negative (defined) latency.