The NSN Lookup API gives programs and AI agents read access to U.S. federal catalog data (FLIS): National Stock Numbers, manufacturer part numbers, CAGE codes, Federal Supply Classes and Item Name Codes.
| I want to | Read |
|---|---|
| Make my first call | Getting started |
| See every endpoint and parameter | Endpoints |
| Know what a field or code means | Data dictionary |
| Connect an AI agent (Claude, ChatGPT, others) | MCP for AI agents |
| Know what happens when the API changes | Versioning |
| Handle errors and rate limits | Errors and limits |
Base URL: https://api.nsnlookup.com
Current version: v19 (all paths start with /v19)
Format: JSON over HTTPS, GET only. Property names are camelCase. Properties with no value are left out of the response.
curl -H "X-Api-Key: YOUR_KEY" https://api.nsnlookup.com/v19/nsn/5305-00-123-4567
{
"nsn": "5305-00-123-4567",
"niin": "001234567",
"fsc": "5305",
"itemName": "SCREW,MACHINE",
"demil": "A",
"references": [
{ "partNumber": "MS35338-44", "cage": "96906", "rncc": "2", "rnvc": "2", "historical": false }
]
}
The values above are an illustration, not a real catalog record.