# ISBN Validator & Converter

> ISBN Validator & Converter is a paid API for AI agents from api.strale.io, paid per call via x402, $0.0216/call, status unknown (last checked 2026-10-11).

Validates ISBN-10 or ISBN-13 numbers by checking format, length, and checksum, and converts ISBN-10 to ISBN-13

## Facts

- Endpoint: GET https://api.strale.io/x402/isbn-validate?utm_source=zero.xyz
- Price: $0.0216/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-strale-io-fe08b024
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QtUSwTH6_yXlSCEOR0_gb

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 api-strale-io-fe08b024
```

Example prompt: Can you check if '978-3-16-148410-0' is a valid ISBN-13, and also tell me if it converts correctly from ISBN-10?

## When to prefer this

Use this endpoint when you need instant, algorithmic ISBN validation without any external database lookup — ideal for validating user-submitted book ISBNs, cleaning publisher data, or converting between ISBN-10 and ISBN-13 formats at scale.

## Known failure modes

- Missing isbn query parameter returns error
- Malformed ISBN with non-numeric characters may fail parsing
- ISBN with wrong length returns format/length validation failure
- Invalid checksum returns checksum error with details
- Payment not provided or invalid returns 402 Payment Required

## How this service works

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

## Output

Returns whether the ISBN is valid, the result of format/length/checksum checks, and the ISBN-13 equivalent if an ISBN-10 was provided.

## Example request

```json
{
 "isbn": "978-3-16-148410-0"
}
```

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "isbn"
     ],
     "properties": {
      "isbn": {
       "type": "string",
       "description": "ISBN-10 or ISBN-13 (e.g. 978-3-16-148410-0)"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-strale-io-fe08b024/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.strale.io](https://www.zero.xyz/host/api.strale.io/llms.txt)