ISBN Conversion API - ISBN Converter

A REST API for converting ISBN-10, ISBN-13, EAN-13, and UPC-A codes programmatically. One authenticated GET request returns all applicable equivalents for any valid input code, or a single target format if that's all you need.

Built for developers integrating ISBN conversion into publishing tools, library systems, catalog pipelines, and retail integrations. The API handles checksum validation, format detection, and the 979-prefix edge case. Codes with no ISBN-10 equivalent are returned empty rather than producing a wrong result.

Authentication uses a static API key in the X-API-Key header. Keys are tied to your account and draw from the same credit balance as the web tools: one credit per successful conversion, with 100 free credits refreshed monthly.

Sign in to create API keys.

API Endpoints

Full Conversion

Endpoint: /v1/convert/{code}

Method: GET

Description: Convert a given code (ISBN-10, ISBN-13, EAN, or UPC) to all other applicable formats.

Parameters:

code - The code to convert (required). Can be ISBN-10, ISBN-13, EAN, or UPC.

Headers:

X-API-Key - Your API key (required).

Response Fields:

code - The original input code (or a normalized version if applicable).
ean - EAN code, empty if not applicable.
isbn13 - ISBN-13 code, empty if not applicable.
isbn10 - ISBN-10 code, empty if not applicable.
upc - UPC code, empty if not applicable.

Example Request:

curl -H "X-API-Key: YOUR_API_KEY" https://api.isbnconverter.com/v1/convert/9780262033848

Example Response:

{
	"code": "9780262033848",
    "ean": "9780262033848",
    "isbn13": "9780262033848",
    "isbn10": "0262033844",
    "upc": ""
}

Single Format Conversion

Endpoint: /v1/convert/{code}/{format}