Penelope Health builds infrastructure for payer medical coverage policy data. It extracts and structures medical policies from major US insurers into a queryable knowledge graph covering more than 500,000 CPT, HCPCS and ICD codes and over two million medical necessity criteria, delivered through a web app and an API. Customers use it to check whether a code is covered, excluded or considered experimental for a given payer and plan, compare coverage across payers, and generate prior authorization requests and appeal letters. The company was founded by Sohum Patel, a Cambridge-trained physician, and Mattijs De Paepe.