A free ISBN is one of the more generous things a publishing platform offers, and one of the least understood. The number itself is real and works at any register. What differs is who the number says published the book, and where it can be used.
Publisher of record
Every ISBN belongs to a registrant, and the registrant is listed as the publisher in trade databases. When you buy your own numbers, your name or imprint is the publisher. When a platform assigns one from its block, the platform's imprint is.
With Amazon KDP, for example, the publisher field reads "Independently published". With other services it is the service's own imprint name. Nobody at a bookstore is confused by this, but some are put off: "Independently published" is a visible flag, and some stores decline to stock titles that carry it.
Portability
A platform-assigned ISBN can usually be used only on that platform. If you decide to move from KDP to a different printer, or to add IngramSpark for bookstore distribution, you cannot take the number with you. The new edition needs a new ISBN, and the two editions of the same book now appear as separate products.
An ISBN you own goes wherever you go. Print with one company this year and another next year, and the book remains one book.
Metadata control
Your record in trade databases comes from the registrant. With your own ISBN you set the publisher name, imprint and details. With a platform ISBN, the platform supplies the record and your ability to correct it runs through their support desk.
When free is fine
- You sell only on that platform and do not expect that to change.
- You are testing a book or a format and may not keep it in print.
- The book is a personal project, a workbook for your own clients or a gift edition.
- Your national agency charges for ISBNs and the sum matters to you now.
When to buy your own
- You want bookstores and libraries to be able to order the book.
- You might change printers or add a wholesaler later.
- You are building an imprint, even a one-person one, and want it on the record.
- You live in a country where ISBNs are free, such as Canada, in which case there is no trade-off at all.
Either way, keep control of the rest
The ISBN decision is about the trade's systems. The things readers actually touch, the barcode and QR code on the cover, the page they land on, the links to buy, are yours to control regardless of whose block the number came from.
ScanSpine works the same with a platform ISBN as with your own, and with no ISBN at all. Enter whichever number you have and the record, codes and page follow.