Barcode · ISBN · GTIN validation

Book ISBN or retail barcode — hyphenated or plain. Check the digit with a no-key demo quota; get 978↔ISBN-10 conversion and TR GS1 prefix (868/869) hints. Not a catalogue lookup.

Idle $0 This validator is free (demo quota) Paid = API key for software Not a catalogue / GS1 lookup

A matching check digit is arithmetic consistency. It does not prove the title exists in a national bibliography or the SKU is listed in a brand catalogue.

Validation form

Results appear here

Pick ISBN or GTIN, keep the sample or paste your own, then Validate. Valid/invalid + formatting show here.

Which endpoints?

POST /v1/id/isbn · /v1/id/gtin — deterministic, no upstream. ISBN-10↔13 conversion and GTIN-8/12/13/14 check digits.

Is this an ISBN / GS1 catalogue lookup?

No. Only check-digit and format validation. Existence of a title or SKU is not proven; no upstream is called.

Free vs paid?

The playground is an anon IP demo quota. A paid API key is for software integration, higher quotas and call metering. Idle $0.