ISMN validate API

Validates an ISMN-13 (printed-music identifier, 9790 prefix, GS1 mod-10), accepting the legacy 'M' form. Answers 'Is this ISMN valid?', 'Does this music number have a valid check digit?'.

Price$0.02per request

MethodPOST

Route/v1/validate/ismn

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

ismnmusicsheet-musiccheck-digitmod-10validategs1scorepublishing

API URLhttps://x402.hexl.dev/v1/validate/ismn

Integration docs

Example request

{
  "ismn": "979-0-2600-0043-8"
}

Example response

{
  "valid": true,
  "reason": "Valid ISMN-13 (prefix 9790, mod-10 OK).",
  "normalized": "9790260000438",
  "checkDigit": {
    "expected": "8",
    "actual": "8"
  }
}

Input schema

{
  "type": "object",
  "required": [
    "ismn"
  ],
  "properties": {
    "ismn": {
      "type": "string",
      "description": "13-digit ISMN starting 9790 (or legacy M...).",
      "examples": [
        "979-0-2600-0043-8"
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}