Query the NPPES NPI registry API to validate provider identities, retrieve taxonomy codes, and build a provider directory

Verified steps

1. Access the NPPES NPI Registry API (no authentication required for public data): GET requests to the registry API endpoint with query parameters such as number (NPI), name (first_name, last_name or organization_name), taxonomy description, city, state, and postal_code
2. Parse the response JSON: results array contains provider objects with 'number' (NPI), 'enumeration_type' (NPI-1 individual, NPI-2 organizational), 'basic' object (name, status, certification date), 'addresses' array (practice and mailing locations), and 'taxonomies' array
3. From 'taxonomies': extract 'code' (10-character NUCC taxonomy code), 'desc' (taxonomy description), 'primary' boolean flag (true for the primary specialty), and 'state'/'license' for state license numbers when present
4. Validate provider identity by matching the returned NPI status field to 'A' (active) — an 'D' (deactivated) or missing NPI indicates the provider is not eligible for billing; also check the enumeration date to confirm the NPI predates the claim service date
5. For building a provider directory, perform bulk download via the NPPES NPI data dissemination file (full replacement or weekly incremental) rather than individual API calls; the dissemination file is available as a CSV download from the CMS website
6. Cache NPI lookup results with a weekly refresh cycle aligned with the NPPES weekly update cycle; implement a staleness check so that provider records older than 7 days are re-queried before being used for claim submission