Look up US healthcare providers in the CMS NPPES registry — the authoritative directory of National Provider Identifiers (NPIs). Give an exact 10-digit NPI, or search by provider last name (+ optional first name), or organization name, optionally narrowed by state and taxonomy/specialty. Returns each provider with NPI, entity type (individual vs organization), status, name/credential/gender or organization name, sole-proprietor flag, enumeration + last-updated dates, primary taxonomy, the full taxonomy list (code, description, primary flag, state license), and practice/mailing addresses with phone. Free, public-domain (CMS). The canonical "who is this NPI / find this provider" lookup for healthcare, claims, and credentialing agents.