One address reaches the people who build this site:

hello@tolerence.net

The reports we can act on fastest include the device, browser (and version), and what the click did — “beats bunch up above 240 BPM on Safari iOS 18” is immediately testable; “it sounds weird” needs a reply round-trip. Screenshots of the tool mid-run help more than descriptions of sound.

Also welcome:

• Wrong facts — if a tempo range, formula or date on a guide page is wrong, say so and we’ll fix it with a source.
• Feature requests — subdivisions, meters or practice modes you wish existed. Small and specific gets built; “make it an app” gets parked.
• Accessibility problems — if a control can’t be reached, read or operated, that’s a bug here, full stop.

We answer everything, usually within a few days.