NPI Registry (NPPES): what it returns, and whether it works in Clay

NPI Registry (NPPES) is partly covered in Clay. It is best for Lead lists, Buying signals. Pricing: Free. Access: Free, no API key; API returns up to 200 results per request with a skip parameter for paging (per CMS docs, skip is capped; docs page is client-rendered and the cap could not be read here); bulk files free; public domain..

Data domains: Healthcare, Government, Contact, Company, People, Phone.

What does NPI Registry (NPPES) return?

Official fields: result_count; results[].number; enumeration_type; created_epoch; last_updated_epoch; basic.organization_name; basic.first_name; basic.last_name; basic.credential; basic.sole_proprietor; basic.gender; basic.enumeration_date; basic.last_updated; basic.certification_date; basic.status; basic.organizational_subpart; basic.parent_organization_legal_business_name; basic.authorized_official_first_name; authorized_official_last_name; authorized_official_name_prefix; authorized_official_title_or_position; authorized_official_telephone_number; authorized_official_credential; addresses[].address_purpose (LOCATION, MAILING); address_type; address_1; address_2; city; state; postal_code; country_code; country_name; telephone_number; fax_number; taxonomies[].code; desc; primary; state; license; taxonomy_group; identifiers[]; endpoints[]; other_names[]; practiceLocations[]. Observed limit: a request with limit=201 returned 200 results.

What can you derive from it?

1. Provider universe: organizations and practitioners by taxonomy (clinic type, specialty) and geography. 2. New practices: NPI-2 enumeration_date in the last 90 days signals openings. 3. Decision makers: authorized official name, title and phone for organizations. 4. Hierarchy: parent_organization_legal_business_name and organizational_subpart link sites to systems. 5. Closures: deactivation file and status changes.

How would a GTM team use it?

1. TAM build: all NPI-2 organizations with a given taxonomy in target states, with location phone. 2. Revenue trigger: newly enumerated organizations in a specialty for practice-management, RCM and supplies vendors. 3. Buyer map: health systems and their subparts by city. 4. Diligence: verify a target's provider counts and locations. 5. Market map: provider density by county for site selection.

What are the caveats?

Not a native Clay integration as of 2026-10-17 (checked against Clay's integrations catalog). Can be called through Clay's HTTP API column where an API exists. Self-reported and often stale addresses and phones; many NPI-1 records are individuals, which is personal data of professionals, so keep targeting at NPI-2 organizations and authorized officials in their business role. Taxonomy is declared, not verified; no revenue, volume or payer data. Partial overlap: Definitive Healthcare (in Clay) covers healthcare organizations and providers with added firmographics; NPPES is the free raw registry behind such products.