look up provider NPIs via the NPPES NPI Registry API

Steps

1. Send a GET request to https://npiregistry.cms.hhs.gov/api/ with query parameters such as number (for direct NPI lookup), first_name, last_name, organization_name, or taxonomy_description.
2. Include version=2.1 in the query string to use the current API version, which returns richer address and taxonomy data.
3. Parse the JSON response: results[] contains provider records; each has basic (name, NPI, enumeration type) and addresses[] and taxonomies[] arrays.
4. Filter results by taxonomy code if you need providers of a specific specialty (e.g. 207Q00000X for family medicine); taxonomy codes follow the NUCC Health Care Provider Taxonomy.
5. Use the limit and skip parameters for pagination when a query may return many results (default and maximum limits are documented in the API spec).
6. NPI records are public data and require no API key; however, build in retry logic and respect rate limits to avoid being throttled.