# fittings RxNorm NDC Crosswalk

> fittings RxNorm NDC Crosswalk is a paid API for AI agents from fittings.sh, paid per call via x402, $0.01298/call, status unknown (last checked 2026-09-14).

Maps an RxNorm concept (RxCUI) or drug name to all associated NDC package codes in 5-4-2 format, or reverse-maps an NDC code to its RxCUI with active status and history.

## Facts

- Endpoint: GET https://fittings.sh/v1/rxnorm/ndc-crosswalk
- Price: $0.01298/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fittings-rxnorm-ndc-crosswalk-db1dc2cb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VrqJl8kfKnHWAb-RiV2Ph

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fittings-rxnorm-ndc-crosswalk-db1dc2cb
```

Example prompt: What are all the NDC package codes associated with RxCUI 213269? Give me up to 50 results in 5-4-2 format.

## When to prefer this

Use this endpoint when you need to translate between RxNorm concept identifiers (RxCUIs) or human-readable drug names and NDC package codes, or when you need to reverse-map an NDC code back to its RxNorm concept with active/inactive status. Prefer this over manual NLM API queries when you want a simple, pay-per-call REST interface without managing API keys or complex pagination.

## Known failure modes

- Drug name not matched exactly — returns empty or incorrect set; try using RxCUI directly
- RxCUI not found — returns empty NDC list if concept does not exist in RxNorm
- NDC not recognized — reverse lookup returns no RxCUI if NDC is not in the database
- Limit out of range — error if limit parameter is outside 1-500
- Missing required query parameter — error if none of rxcui, name, or ndc is provided

## How this service works

Map an RxNorm concept or drug name to every associated NDC package code in 5-4-2 form, or reverse-map an NDC to its RxCUI with active status and history.

## Output

Returns a list of NDC package codes in 5-4-2 format associated with the queried RxCUI or drug name, or for a reverse lookup returns the RxCUI with its active status and historical records for the given NDC code.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "ndc": {
       "type": "string",
       "description": "NDC package code to reverse-map, e.g. 0781-1506-10"
      },
      "name": {
       "type": "string",
       "description": "Drug name, resolved to an RxCUI by exact match first"
      },
      "limit": {
       "type": "number",
       "description": "Maximum NDCs returned, 1-500, default 100"
      },
      "rxcui": {
       "type": "string",
       "description": "RxNorm concept id, e.g. 213269"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fittings-rxnorm-ndc-crosswalk-db1dc2cb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fittings.sh](https://www.zero.xyz/host/fittings.sh/llms.txt)