ISBN Validator is a comprehensive tool for validating and parsing ISBN-10 and ISBN-13 book identification numbers. It validates checksums and provides detailed information about each ISBN component.
Try it — live request, no key required
No key required to try it. Get a key to use it in your app.
{
"status": "ok",
"error": null,
"data": {
// ISBN Validator response payload
}
}
About the ISBN Validator API
ISBN Validator works by analyzing ISBN-10 and ISBN-13 numbers, validating their checksum algorithms, and extracting information about the group, publisher, and title identifiers. Handles both formats with or without separators.
What people use it for
- Book Cataloging
- Validate ISBNs when adding books to library catalogs or inventory management systems
- E-commerce
- Verify ISBN accuracy in book listings on e-commerce platforms to prevent listing errors
- Publishing
- Validate ISBNs during book registration and publishing workflows to ensure correct formatting
- Data Quality
- Check ISBN validity in book databases during data cleaning and migration projects
Ways to call it
One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.
- JSON
- Default REST response
- XML
- Markup format
- YAML
- Human-readable
- CSV
- Tabular export
- GraphQL
- Query language
- MCP
- For AI agents
Other ways to use ISBN Validator
Same data, same APIVerve account, same credit balance — one key works on all of them.
What does the ISBN Validator API do?
How do I authenticate ISBN Validator API requests?
How much does the ISBN Validator API cost?
How fast is the ISBN Validator API?
What response formats does the ISBN Validator API support?
What HTTP method does the ISBN Validator API use?
Request parameters — GET /v1/isbnvalidator
Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.
Required
| Parameter | Type | Example | Description |
|---|---|---|---|
isbnRequired | string | 978-0-306-40615-7 | The ISBN number to validate (ISBN-10 or ISBN-13, with or without separators) |
curl "https://api.apiverve.com/v1/isbnvalidator?isbn=978-0-306-40615-7" \
-H "x-api-key: YOUR_API_KEY"Authentication
Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.
| Header | When | Value |
|---|---|---|
x-api-keyRequired | Every request | Your API key. Header names are case-insensitive, so X-API-Key is the same header. |
AuthorizationAlternate | Instead of the above | Bearer <key> — for clients that only expose bearer auth. Resolves to the same account and the same billing. |
A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.
Response — GET /v1/isbnvalidator
Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.
{
"status": "ok",
"error": null,
"data": {
"valid": true,
"isbn": "978-0-306-40615-7",
"type": "ISBN-13",
"normalized": "9780306406157",
"formatted": "978-0-306-40615-7",
"checksum_valid": true,
"prefix": "978",
"group": "0",
"publisher": "306",
"title": "40615",
"check_digit": "7",
"error": null
}
}
Response fields
Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.
| Field | Type | Example | Description |
|---|---|---|---|
valid | boolean | true | Whether the ISBN is valid |
isbn | string | "978-0-306-40615-7" | Normalized ISBN number |
type | string | "ISBN-13" | ISBN format (ISBN-10 or ISBN-13) |
normalized | string | "9780306406157" | The ISBN with hyphens and spaces removed |
formattedPremium | string | "978-0-306-40615-7" | ISBN with proper hyphenation |
checksum_valid | boolean | true | Whether the check digit matches the rest of the number |
prefix | string | "978" | GS1 prefix, 978 or 979 for a 13-digit ISBN |
group | string | "0" | Registration group, identifying the country or language area |
publisher | string | "306" | Publisher element of the ISBN |
title | string | "40615" | Title element, identifying the edition within the publisher |
check_digitPremium | string | "7" | Check digit value |
error | object | null | Why the ISBN was rejected; null when it is valid |
Response headers
Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.
| Header | What it carries |
|---|---|
x-api-remaining-credits | Credits left in the current cycle |
x-api-credits-used | Credits spent in the current cycle |
x-api-max-credits | The allowance for the cycle |
x-api-version | Version of the endpoint that answered |
Errors
Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.
| Status | Meaning | What to do |
|---|---|---|
400 | Input was rejected | Read error; it names the parameter that has to change. |
401 | Key missing or invalid | Check the header name and the key value. |
403 | Key valid, but not permitted here | A key restriction or an IP allow-list — never a bad key. |
429 | Rate limited, or out of credits | Read error to tell them apart, then back off or top up. |
What a call costs — 2 credits per call
Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.
| Plan | Per month | Credits | ISBN Validator calls | Per 1,000 calls |
|---|---|---|---|---|
| Free | Free | 200 | 100 | Free |
| Starter | $29.99 | 200,000 | 100,000 | $0.30 |
| Pro | $99.99 | 1,000,000 | 500,000 | $0.20 |
| Mega | $299.99 | 4,000,000 | 2,000,000 | $0.15 |
Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.
Call it from cURL — GET /v1/isbnvalidator
No SDK to install — this is a plain HTTPS call to /v1/isbnvalidator with your key in the x-api-key header. Swap in a real key and it runs as-is.
curl "https://api.apiverve.com/v1/isbnvalidator" \
-H "x-api-key: YOUR_API_KEY"Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Node.js — GET /v1/isbnvalidator
Install the Node.js SDK, then call the ISBN Validator API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
npm install @apiverve/isbnvalidatorconst res = await fetch("https://api.apiverve.com/v1/isbnvalidator", {
headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Python — GET /v1/isbnvalidator
No SDK to install — this is a plain HTTPS call to /v1/isbnvalidator with your key in the x-api-key header. Swap in a real key and it runs as-is.
import requests
res = requests.get(
"https://api.apiverve.com/v1/isbnvalidator",
headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from C# / .NET — GET /v1/isbnvalidator
Install the C# / .NET SDK, then call the ISBN Validator API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
dotnet add package APIVerve.API.ISBNValidatorusing var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");
var json = await client.GetStringAsync("https://api.apiverve.com/v1/isbnvalidator");
Console.WriteLine(json);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Go — GET /v1/isbnvalidator
No SDK to install — this is a plain HTTPS call to /v1/isbnvalidator with your key in the x-api-key header. Swap in a real key and it runs as-is.
req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/isbnvalidator", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from PHP — GET /v1/isbnvalidator
No SDK to install — this is a plain HTTPS call to /v1/isbnvalidator with your key in the x-api-key header. Swap in a real key and it runs as-is.
$ch = curl_init("https://api.apiverve.com/v1/isbnvalidator");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);
$response = curl_exec($ch);
echo $response;Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Ruby — GET /v1/isbnvalidator
No SDK to install — this is a plain HTTPS call to /v1/isbnvalidator with your key in the x-api-key header. Swap in a real key and it runs as-is.
require "net/http"
uri = URI("https://api.apiverve.com/v1/isbnvalidator")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.bodyResources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Zero-code embed — one snippet, no backend
Drop an interactive ISBN Validator form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.
Changelog — ISBN Validator API
Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.
Entries are picked up from dated catalog snapshots, so the first one appears after the next snapshot that moves something. A period where nothing changed produces no entry — silence is a valid changelog for the ISBN Validator API.
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