---
title: "ISBN Validation (x402)"
method: GET
path: "/x402/v2/isbn-validate"
tags: ["x402"]
---

# ISBN Validation (x402)

`GET /x402/v2/isbn-validate`

## Request

- Base URL: `https://api.strale.io`
- URL: `https://api.strale.io/x402/v2/isbn-validate`
- Auth: none required

Validate an ISBN-10 or ISBN-13 number. Checks format, length, and checksum. Converts ISBN-10 to ISBN-13. Pure algorithmic — instant.

## Query parameters

- `isbn` string, required: ISBN-10 or ISBN-13 (e.g. 978-3-16-148410-0)

## Response `200`

Success

- object
  - `type` string
  - `valid` boolean
  - `isbn13` string

## Other responses

- `402`: Payment required (x402 — pay with USDC on Base)

---

[API](https://skmtc.dev/strale/apis/strale-api-2.md) · [All operations](https://skmtc.dev/strale/apis/strale-api-2/llms.txt) · [OpenAPI document](https://skmtc.dev/strale/apis/strale-api-2/revisions/a5293878cfc6?raw)