isbn

isbn · Required by Google

Appears in

Book

What is it?

The isbn property provides the International Standard Book Number for a specific edition of a book. ISBNs are unique identifiers assigned to each edition and format, allowing search engines, bookstores, and libraries to identify exactly which version of a book is being referenced.

Google requires ISBN-13 format at the workExample (edition) level.

Why this matters for AEO

When a user asks "what is the ISBN for the paperback edition of Dune," AI answer engines pull the isbn field from the matching workExample to provide the exact identifier. Structured ISBN data also lets AI engines cross-reference books across publishers, retailers, and library catalogs.

What the specs say

Schema.org:Text. The ISBN of the book.

Google: Required. "The ISBN-13 of the edition." Source

How to find your value

• Copyright page — Printed inside the book, usually on the verso of the title page
• Barcode — The 13-digit number above or below the barcode on the back cover
• Publisher catalog — Edition-specific listings
• ISBN databases — worldcat.org, isbnsearch.org
• Amazon/bookstores — Product details section

Format and code

Single edition:

{
  "@context": "https://schema.org",
  "@type": "Book",
  "name": "The Catcher in the Rye",
  "author": {"@type": "Person", "name": "J.D. Salinger"},
  "workExample": {
    "@type": "Book",
    "isbn": "9780316769488",
    "bookFormat": "https://schema.org/Paperback"
  }
}

Multiple editions:

{
  "@context": "https://schema.org",
  "@type": "Book",
  "name": "Holt Physical Science",
  "workExample": [
    {
      "@type": "Book",
      "isbn": "9780030426599",
      "bookFormat": "https://schema.org/EBook"
    },
    {
      "@type": "Book",
      "isbn": "9780030426582",
      "bookFormat": "https://schema.org/Hardcover"
    }
  ]
}

Common invalid patterns:

{
  "isbn": "978-0-316-76948-8"
}

Remove hyphens. Google expects a plain 13-digit string.

Webflow implementation

Static pages

Add isbn as a plain text string (no hyphens) inside each workExample object in your Book JSON-LD block in Page Settings > Custom Code > Footer Code.

CMS template pages

Create a CMS plain text field for ISBN. Ensure contributors enter the 13-digit number without hyphens or spaces. Reference it in a custom code embed within the workExample object.

In Schema HQ

The isbn field does not currently generate Book markup. Add ISBN data manually through Webflow custom code.

Real examples

From JSONld.com:

{
  "@context": "https://schema.org",
  "@type": "Book",
  "name": "The Catcher in the Rye",
  "workExample": {
    "@type": "Book",
    "isbn": "0316769487",
    "bookFormat": "https://schema.org/Paperback",
    "inLanguage": "en"
  }
}

From Schema.org Book Example:

{
  "@context": "https://schema.org",
  "@type": "Book",
  "name": "Holt Physical Science",
  "workExample": {
    "@type": "Book",
    "isbn": "9780030426599",
    "bookFormat": "https://schema.org/EBook"
  }
}

Related fields

• bookFormat
• numberOfPages
• author
• name

FAQ

Should I use ISBN-10 or ISBN-13?

Google specifies ISBN-13. If you only have an ISBN-10, convert it by prepending 978 and recalculating the check digit. Online converters handle this automatically.

Where does isbn go: on the Book or on workExample?

On workExample. The top-level Book represents the abstract work. Each workExample is a specific edition with its own ISBN, format, and language. Different editions of the same book have different ISBNs.

Should I include hyphens in the ISBN?

No. Use a plain digit string: "9780316769488", not "978-0-316-76948-8". Google and most parsers expect digits only.