For a single permit lookup or anything requiring official confirmation — issuance, occupancy sign-off, final inspection — the NYC DOB NOW / BIS is the source of record. Go directly to the City of New York portal for those.
For ongoing monitoring across multiple New York City permits, a third-party service such as SignedOff reduces manual lookups and surfaces published status changes by email. The typical use case is a contractor, architect, or project manager with several active New York City jobs across different systems or stages where checking each official source daily is impractical.
Both tools draw from the same underlying permit record — the NYC DOB NOW / BIS is always the system of record; SignedOff is a monitoring layer on top of it.