An ISBN is an international, product-level identifier used across the book supply chain. A Google Books volume ID is Google’s opaque identifier for a volume record in Google Books and its API. A GGKEY is a Google-generated catalog identifier that partners can request when a book has no ISBN or EAN; Google says GGKEYs are used only within Google.
They are not interchangeable. Use an ISBN when the book product needs standard identification across publishers, distributors, retailers, libraries, and metadata systems. Use the Google Books volume ID when linking to or retrieving a specific Google Books record. Use a GGKEY inside Google’s Partner Center when the book has no ISBN and Google offers that option.
A book can have all three. The ISBN identifies the edition and format in the wider supply chain, while Google’s identifiers locate Google-specific records or catalog entries.
|
Aspect |
ISBN | Google Books volume ID |
GGKEY |
| System owner | International ISBN system and registration agencies | Google Books | Google Play Books Partner Center |
| Primary scope | Book-industry supply chain | Google Books site and API | Google’s internal partner workflow |
| Purpose | Identify a specific publication product | Identify a Google Volume resource | Identify a partner book without ISBN or EAN |
| Typical format | 13 digits; legacy ISBN-10 also exists | Opaque alphanumeric string | Google-generated key, often shown with GGKEY |
| Assigned by | Publisher using an agency allocation or agency process | Google when the partner requests the option | |
| Identifies | Edition, language, and product form | A specific Google Books record | A Google catalog item |
| Portable outside Google | Yes, across systems that support ISBN | No | No |
| Required to use Google Books | No | Created for Google records | Optional route for a book without ISBN or EAN |
| Where it appears | Metadata feeds, catalogs, listings, and book barcodes | Volume resource and books.google.com URL | Partner Center catalog and file workflow |
| Format or edition handling | Distinct products require distinct ISBNs | Records may represent editions or sources differently | Specific to the Google partner entry |
| Barcode use | ISBN-13 can be encoded in an EAN-13 book barcode | Not an ISBN barcode value | Not an ISBN barcode value |
The International Standard Book Number is a standardized identifier for a specific monographic publication, edition, language, and product form. Modern ISBNs contain 13 digits; ISBN-10 remains in legacy records and can often be converted to the corresponding 978 ISBN-13.
Publishers obtain ISBNs through the registration agency responsible for their country or territory. In the United States, Bowker is the official ISBN agency. A publisher then assigns an ISBN from its allocation to one qualifying product and supplies the matching metadata.
A paperback, hardcover, separately available ebook format, audiobook product, translation, large-print edition, and substantially revised edition are evaluated as distinct products. An unchanged reprint keeps its ISBN. The identifier is not a copyright registration, sales counter, retailer account, or guarantee that every database has current metadata.
An ISBN can appear in distributor feeds, bookstore systems, library records, bibliographic databases, catalog pages, and an EAN-13 book barcode. Its value is cross-system interoperability: the same publisher-owned ISBN should follow the same unchanged product through participating channels.
The Google Books API represents a book record as a Volume resource. The resource has an id field that Google describes as the unique identifier for that volume. This opaque alphanumeric value commonly appears in a Google Books URL after the id parameter and in API responses.
For example, a URL can take the form https://books.google.com/books?id=OIPXDwAAQBAJ. The alphanumeric value is useful for opening that Google record, storing a Google-specific reference, calling the API by volume ID, or embedding Google Books features.
A Google volume record can also expose industryIdentifiers such as ISBN-10 and ISBN-13 in its volumeInfo data. That illustrates the relationship: the volume ID identifies Google’s record, while the ISBN identifies the book product under an industry standard.
Do not assume that one conceptual work, one ISBN, and one Google volume record always map perfectly. Google can hold records for different editions, formats, or sources, and metadata fields may be incomplete or normalized differently. Verify the ISBN and product details before connecting records automatically.
In Google Play Books Partner Center, a publisher adding a book without an ISBN or EAN can select “Get a Google book ID (GGKEY).” Google’s ISBN help states that an ISBN is not required to submit a book to Google Books or sell it on Google Play and that GGKEYs are only used internally within Google.
A GGKEY is therefore a platform identifier, not an ISBN substitute for external distribution. It can identify the book in Google’s partner workflow and appear in catalog searches or file-naming instructions, but it does not become a recognized ISBN in bookstore, distributor, or library systems.
Also avoid using “Google Book ID” without context. Some people mean the Google Books API volume ID; Partner Center documentation may use “Google book ID” when offering a GGKEY. Name the exact identifier in documentation, databases, and support requests.
You do not choose between an ISBN and a Google volume ID as if they perform the same job. If a widely distributed paperback is indexed in Google Books, keep its ISBN in the master product record and store the Google volume ID in a separate platform-ID field.
The paperback receives its own ISBN. If the ebook is a separately available product and the publisher chooses to identify it with an ISBN, it receives another. Google may create volume records with Google volume IDs for each indexed record. If a Google-only book has no ISBN and the Partner Center permits it, Google can assign a GGKEY.
The application searches Google Books with an ISBN query, checks the returned industryIdentifiers, and stores both the ISBN and selected volume.id. The ISBN supports product matching across sources; volume.id supports deep links and future Google API calls. Low-confidence or conflicting edition matches go to review.
The same title appears as a hardcover in a library catalog and an ebook in Google Books. Do not merge them by title. Compare ISBN, publisher, publication date, language, edition statement, and format. Different products should retain different ISBNs and may have different Google volume IDs.
A publisher can still add an eligible book to Google’s partner system if the current workflow offers a GGKEY. That makes the item manageable inside Google, but it does not create cross-industry identification. If wider distribution later requires an ISBN, obtain and assign the correct ISBN through the applicable national process; do not relabel the GGKEY as an ISBN.
Record the ISBN-13, ISBN-10 if applicable, title, contributors, publisher or imprint, language, edition, format, and publication date. Keep one row per product.
Use the Google Books API ISBN query or search the exact number in Google Books. ISBN matching is more precise than title-only matching but still requires verification.
Compare industryIdentifiers and descriptive fields with the master record. Reject a result that represents another binding, language, edition, or publisher.
Use fields such as isbn13, isbn10, google_volume_id, and ggkey. Do not overload one generic book_id column unless it also stores the identifier type and issuing system.
Keep multiple candidate volume IDs when Google has distinct records, select a canonical match using documented rules, and log confidence. Do not manufacture a Google ID or substitute an ISBN when no Google record is found.
API and catalog records can change. Save the source and retrieval date, respect current API terms and quotas, and refresh data that affects live links, availability, or display.
No. A Google volume ID or GGKEY works within Google’s systems. It is not the international product identifier used across ISBN-based supply-chain systems.
No. Google states that an ISBN is not required to submit a book to Google Books or sell it on Google Play. For books without an ISBN or EAN, eligible Partner Center workflows can provide a GGKEY.
Open the Google Books record and look for the opaque value associated with the id parameter, or read the id field of the Volume resource returned by the Google Books API.
It appears in Google Play Books Partner Center after Google assigns it to a book without an ISBN or EAN. Partner documentation and catalog search may display it with the GGKEY prefix.
Google’s record model and source ingestion can produce multiple candidate records or edition relationships. Design workflows to verify industryIdentifiers and product metadata instead of assuming a permanent one-to-one mapping.
An accurate ISBN can help systems match a product and connect metadata, but it is not a ranking guarantee. Search visibility also depends on content quality, metadata consistency, indexing, links, demand, and platform behavior.
Not as an ISBN. A standard book barcode encodes an ISBN-13 within EAN-13 conventions. Follow Google’s file and catalog instructions for GGKEYs instead.
Use the ISBN as the portable industry identifier for a specific edition and format. Use the Google Books volume ID to reference a Google Books Volume record. Use a GGKEY only for Google’s internal partner workflow when no ISBN or EAN is supplied. Store all identifiers with their types, verify product-level metadata before mapping them, and never substitute a platform ID for an ISBN in external distribution.
