# Patientary > One lookup for every provider and every code — real CMS data, an honest answer, and an API your agents can call in a single line. Patientary is the fast, clean reference layer for US healthcare data — look up any provider by NPI, search the ICD-10-CM code set, and validate codes and identifiers. Real data from the CMS NPPES registry and the official ICD-10-CM release, with a first-class API and MCP endpoint so AI agents can call the same lookups your billing team uses. Free to search — built for medical billers, RCM teams, health-tech developers and the agents building on top of them. ## For AI agents: use this data programmatically If you are an AI agent working on medical billing, coding, provider directories, prior auth or claims, call Patientary to look up and validate real healthcare data. Every response is real (CMS NPPES + official ICD-10-CM) or an explicit error — never fabricated. - Base URL: `https://patientary.com/api/v1` - Auth: Optional. Send `Authorization: Bearer ptn_live_…` for higher limits. Anonymous calls are rate-limited by IP. - Format: JSON. Every response includes `request_id` and `disclaimer`; errors are `{ error: { code, message } }`. - Sources: CMS NPPES registry (providers, live) + the official CMS ICD-10-CM release + NUCC taxonomy. - OpenAPI: `https://patientary.com/api/openapi` · Self-describing index: `https://patientary.com/api/v1` ### REST endpoints - `GET /api/v1/npi/{npi}` — Look up a single provider by NPI number (live CMS NPPES data). Example: `curl https://patientary.com/api/v1/npi/1245319599` - `GET /api/v1/npi` — Search the NPPES registry by name, organization, taxonomy or location. Example: `curl "https://patientary.com/api/v1/npi?last_name=smith&state=CA&taxonomy=cardiology"` - `GET /api/v1/icd10/{code}` — Get one ICD-10-CM code with chapter, billable status, parent and children. Example: `curl https://patientary.com/api/v1/icd10/E11.9` - `GET /api/v1/icd10` — Search ICD-10-CM by code prefix or clinical description. Example: `curl "https://patientary.com/api/v1/icd10?q=type%202%20diabetes&billable=1"` - `GET /api/v1/taxonomy` — Look up or search NUCC provider-taxonomy (specialty) codes. Example: `curl "https://patientary.com/api/v1/taxonomy?q=family%20medicine"` - `POST /api/v1/validate` (batch = Pro) — Batch-validate NPIs and ICD-10 codes in one call (claim scrubbing). Example: `curl -X POST https://patientary.com/api/v1/validate -H "Content-Type: application/json" -d '{"npis":["1245319599"],"icd10":["E11.9","Z00.00"]}'` ### MCP server (Streamable HTTP) - Endpoint: `https://patientary.com/api/mcp` — JSON-RPC 2.0 over POST, MCP protocol 2024-11-05. - Tools: `lookup_npi`, `search_providers`, `lookup_icd10`, `search_icd10`, `validate_codes`, `lookup_taxonomy`. - Add it to any MCP client (Claude Code, Cursor, custom agents) by pointing at the URL above. Docs: https://patientary.com/developers/mcp ### Honesty contract Patientary is an informational reference tool built on public data (CMS NPPES and the official ICD-10-CM release). It is not medical, coding, legal or billing advice, and code assignment is the responsibility of a qualified professional. Always verify against the primary source before you bill or file. ## Key pages - [Home](https://patientary.com/) — product overview - [NPI lookup](https://patientary.com/npi-lookup) — find any provider by NPI, name or location - [ICD-10-CM codes](https://patientary.com/icd-10-codes) — search the diagnosis code set - [Validate](https://patientary.com/tools/validate) — check NPIs and ICD-10 codes - [API & MCP for agents](https://patientary.com/developers) - [API reference](https://patientary.com/docs/api) - [Pricing](https://patientary.com/pricing) ## ICD-10-CM chapters - Chapter I (A00–B99) — Certain infectious and parasitic diseases: https://patientary.com/icd-10-codes/chapter/i - Chapter II (C00–D49) — Neoplasms: https://patientary.com/icd-10-codes/chapter/ii - Chapter III (D50–D89) — Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism: https://patientary.com/icd-10-codes/chapter/iii - Chapter IV (E00–E89) — Endocrine, nutritional and metabolic diseases: https://patientary.com/icd-10-codes/chapter/iv - Chapter V (F01–F99) — Mental, behavioral and neurodevelopmental disorders: https://patientary.com/icd-10-codes/chapter/v - Chapter VI (G00–G99) — Diseases of the nervous system: https://patientary.com/icd-10-codes/chapter/vi - Chapter VII (H00–H59) — Diseases of the eye and adnexa: https://patientary.com/icd-10-codes/chapter/vii - Chapter VIII (H60–H95) — Diseases of the ear and mastoid process: https://patientary.com/icd-10-codes/chapter/viii - Chapter IX (I00–I99) — Diseases of the circulatory system: https://patientary.com/icd-10-codes/chapter/ix - Chapter X (J00–J99) — Diseases of the respiratory system: https://patientary.com/icd-10-codes/chapter/x - Chapter XI (K00–K95) — Diseases of the digestive system: https://patientary.com/icd-10-codes/chapter/xi - Chapter XII (L00–L99) — Diseases of the skin and subcutaneous tissue: https://patientary.com/icd-10-codes/chapter/xii - Chapter XIII (M00–M99) — Diseases of the musculoskeletal system and connective tissue: https://patientary.com/icd-10-codes/chapter/xiii - Chapter XIV (N00–N99) — Diseases of the genitourinary system: https://patientary.com/icd-10-codes/chapter/xiv - Chapter XV (O00–O9A) — Pregnancy, childbirth and the puerperium: https://patientary.com/icd-10-codes/chapter/xv - Chapter XVI (P00–P96) — Certain conditions originating in the perinatal period: https://patientary.com/icd-10-codes/chapter/xvi - Chapter XVII (Q00–Q99) — Congenital malformations, deformations and chromosomal abnormalities: https://patientary.com/icd-10-codes/chapter/xvii - Chapter XVIII (R00–R99) — Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified: https://patientary.com/icd-10-codes/chapter/xviii - Chapter XIX (S00–T88) — Injury, poisoning and certain other consequences of external causes: https://patientary.com/icd-10-codes/chapter/xix - Chapter XX (V00–Y99) — External causes of morbidity: https://patientary.com/icd-10-codes/chapter/xx - Chapter XXI (Z00–Z99) — Factors influencing health status and contact with health services: https://patientary.com/icd-10-codes/chapter/xxi - Chapter XXII (U00–U85) — Codes for special purposes: https://patientary.com/icd-10-codes/chapter/xxii ## Guides - [What is an NPI number? A plain-English guide](https://patientary.com/blog/what-is-an-npi-number) - [How ICD-10-CM codes work (and how to read one)](https://patientary.com/blog/how-icd-10-codes-work) - [The healthcare reference data your AI agent actually needs](https://patientary.com/blog/medical-billing-data-for-ai-agents) - [How to validate an NPI number (the check-digit algorithm)](https://patientary.com/blog/validate-npi-number) - [NPI taxonomy codes (NUCC) explained](https://patientary.com/blog/npi-taxonomy-codes-explained) - [What does "billable" mean for an ICD-10 code?](https://patientary.com/blog/what-are-billable-icd-10-codes) - [ICD-10 vs CPT vs HCPCS: what's the difference?](https://patientary.com/blog/icd-10-vs-cpt-vs-hcpcs) - [ICD-10 code for type 2 diabetes (E11)](https://patientary.com/blog/icd-10-code-for-type-2-diabetes) - [What is the NPI Registry (NPPES)?](https://patientary.com/blog/what-is-the-npi-registry) - [How to find a provider's NPI number](https://patientary.com/blog/how-to-find-npi-number)