@retailerapi/identifier

Zero-dependency detector for product identifiers. Recognizes UPC-12, EAN-13, ISBN-10, ISBN-13, GTIN-14, Amazon ASIN, and Walmart item_id from a raw string. Returns the type plus a normalized form, so your code can dispatch to the right lookup API.

npm i @retailerapi/identifier

import { detectIdentifier } from '@retailerapi/identifier';

detectIdentifier('194629116676');
// { type: 'upc', normalized: '194629116676' }

detectIdentifier('978-0-553-21311-9');
// { type: 'isbn', normalized: '9780553213119' }

detectIdentifier('B07ABCDEFG');
// { type: 'asin', normalized: 'B07ABCDEFG' }

detectIdentifier('19667262713');
// { type: 'item_id', normalized: '19667262713' }

API

type IdentifierType = 'upc' | 'ean' | 'isbn' | 'gtin' | 'item_id' | 'asin';

interface DetectedIdentifier {
  type: IdentifierType;
  normalized: string;
}

detectIdentifier(raw: string): DetectedIdentifier | null;
identifierType(raw: string): IdentifierType | null;   // shortcut
isIdentifier(raw: string): boolean;                   // shortcut

Detection rules

| Length | Prefix | Detected as | |---|---|---| | 10 chars, last is digit or X | — | isbn (ISBN-10) | | 13 digits | 978 or 979 | isbn (ISBN-13) | | 13 digits | anything else | ean | | 14 digits | starts with 0 | strips the zero, detects again | | 14 digits | non-zero | gtin | | 12 digits | — | upc | | B0 + 8 alphanumeric | — | asin | | 6-11 or 12+ digits | — | item_id (opaque retailer SKU) |

Inputs are stripped of whitespace, hyphens, and underscores before matching.

What it does NOT do

• Verify check digits. Real-world catalogs routinely surface off-by-one rows; an over-strict validator filters real data. If you need check-digit math, use a dedicated library.
• Normalize across forms (e.g. UPC-12 → EAN-13 by prefixing 0). That's a downstream concern.

Related

• @retailerapi/mcp — MCP server giving Claude/Cursor product-data tools backed by retailerapi.
• retailerapi.com — Unified product API: Walmart, Amazon, eBay, Lowe's, Target, Best Buy, Home Depot. Free tier 1,000 lookups/mo.

License

MIT