Since 00:05 UTC a host on a domain you have not verified can be checked every 30 seconds over HTTP(S) on ports 80 and 443, and every 15 seconds once your account has bought credits. Before, anything under a minute needed a verified domain. Verification still unlocks 15 seconds for everything, TCP, SMTP and DNS checks, any port and custom requests, and 10-second checks still need both a verified domain and a credit purchase. TLS checks on an unverified host stay at once a minute, and ping keeps its own floors. The same rule applies in the form, bulk edit, Quick add, the import and the API, and the import preview says which interval an unverified draft gets.
At the same time, scheduled rounds for intervals under a minute (30, 15 and 10 seconds) now use three probes on three continents instead of half the fleet, so a fast monitor sends about half as many requests to your site as before: around 12 a minute at 30 seconds and 24 at 15, where 15-second checks sent about 42. Since 00:29 UTC the three shadow probes, which check sites alongside the fleet but do not vote, also stay out of rounds under a minute, which brings it to 6 a minute at 30 seconds, 12 at 15 and 18 at 10; they are now listed on the probe page too, marked shadow, so an allow-list built from it is complete. Nothing changes in how an outage is decided: a scheduled round never declares a site down, confirmation rounds still run on every healthy probe, and the quorum rule is the same. Rounds at one minute and slower are unchanged. The probe page now states how many requests to expect per interval.