---
title: "Resolve a NUCC Health Care Provider Taxonomy code -- the..."
method: GET
path: "/api/medical/taxonomy-specialty"
tags: ["medical"]
---

# Resolve a NUCC Health Care Provider Taxonomy code -- the...

`GET /api/medical/taxonomy-specialty`

## Request

- Base URL: `https://2s.io`
- URL: `https://2s.io/api/medical/taxonomy-specialty`
- Auth: API key in header `PAYMENT-SIGNATURE`

Resolve a NUCC Health Care Provider Taxonomy code -- the specialty code returned by medical.npi and printed on every NPPES record -- into its human specialty: grouping (top level, e.g. "Allopathic & Osteopathic Physicians"), classification (e.g. "Anesthesiology"), specialization, the official display name, and the section (Individual vs Non-Individual). The decode step every claims, credentialing, and provider-directory agent needs to turn an opaque 10-char taxonomy code into a readable specialty. Data: NUCC code set (public domain), bundled and version-pinned. Note: the CMS Medicare 2-char physician-specialty crosswalk is published only as a PDF, so medicareSpecialty is returned null (DEFERRED) rather than guessed.

## Query parameters

- `code` string, required
- `trial` 1

## Other responses

- `200` (unresolved $ref)
- `400`: Invalid request — not charged. error.code: BAD_REQUEST or INVALID_PARAM (parameter validation; error.details.issues lists each problem), MALFORMED_JSON, or a request-specific code. Other client errors: 405 METHOD_NOT_ALLOWED (wrong verb; see the Allow header), 413 PAYLOAD_TOO_LARGE.
- `402`: Payment required. Body is the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients). Also PAYMENT_SETTLE_FAILED (error envelope) when a verified payment failed to settle: error.details.chargeStatus is "not_charged" (retry with a fresh payment) or "unknown" (the authorization may still settle before its deadline — check it before retrying).
- `404`: Not found — NOT_FOUND (or NO_SOURCES / NO_OPINIONS): the requested entity does not exist. Not charged.
- `429`: Too many requests — RATE_LIMITED: our per-IP / per-payer limiter. Not charged; retry after Retry-After.
- `5XX`: Server-side failure. 500 INTERNAL: unexpected error; quote error.errorId (also the X-2s-Error-Id header). 502 UPSTREAM_UNAVAILABLE (or another UPSTREAM_* code): the data provider failed — composite endpoints refuse unbilled when every source fails. 503 SERVICE_PAUSED: endpoint paused by the operator kill switch, retry after Retry-After; 503 SPEND_CAP: daily upstream budget exhausted. 504 UPSTREAM_TIMEOUT. Not charged.

---

[API](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api.md) · [All operations](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/llms.txt) · [OpenAPI document](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/revisions/da4c5caf686e?raw)