NPPES
NPPES, the National Plan and Provider Enumeration System, is the CMS system that assigns National Provider Identifiers and publishes the NPI Registry. Its data is free and official, and it is self-reported by providers.
What is in NPPES?
One record per NPI: provider name, type, taxonomy codes, mailing and practice addresses, phone number and some identifiers. CMS publishes it as the searchable NPI Registry and as downloadable files.
How current is it?
Providers are required to report changes within 30 days, but nobody checks the record against where they actually practice. Many records keep old addresses and phone numbers for years.
How is NPPES used?
As the shared key for matching provider records across systems, and as one input to a directory. Most provider data vendors, Candor Health included, use it alongside other sources.