ISBN Registrant Database: What It Is and How to Use It

If you’re working with books—whether you’re an author, librarian, or book retailer—you’ve probably needed to verify who published a particular book. The ISBN Registrant Database (officially called the Global Register of Publishers or GRP) is your definitive source for this information.

What Is the ISBN Registrant Database?

The Global Register of Publishers (GRP) is the official international database maintained by the International ISBN Agency. It contains records of every publisher that has been assigned an ISBN prefix worldwide.

Think of it as the master directory: when a publisher obtains ISBNs—whether from Bowker in the US, Nielsen in the UK, or any other national ISBN agency—that publisher’s information gets recorded in this centralized database.

What Information Does It Contain?

The GRP typically includes:

Publisher’s registered legal name
Publisher address
ISBN prefix(es) assigned
Imprint names (if the publisher operates under different brands)
Contact information (in some cases)

Why Should Authors Care?

1. Verify Publisher Legitimacy

If you’re working with a publisher or hybrid publishing service, you can check whether they actually exist in the GRP. Scam publishers often use impressive-sounding names but don’t appear in the official database.

2. Find Publisher Imprints

Large publishers often operate multiple imprints. The GRP helps you identify which imprint owns which ISBN prefix—useful for rights researchers and librarians.

3. Self-Publishing Verification

When you purchase your own ISBN, your publisher name gets registered here. This matters for:

Library cataloging
Bookstore ordering systems
Rights verification

How to Access the GRP

Official Portal

The primary access point is: https://grp.isbn-international.org/

This is the official database maintained by the International ISBN Agency. Note that:

Full access may require registration
The interface is designed for industry professionals, not casual users
Data is updated periodically (not real-time)

Alternative Search Tools

Several third-party tools provide easier interfaces to GRP data:

ISBNBarcode.org GRP Search

User-friendly interface
Search by ISBN prefix or publisher name
Available at: https://isbnbarcode.org/grp-search

Book Data Services

Various commercial services offer GRP lookups
Often include additional metadata beyond what’s in the free GRP

Important Limitations

The “One-Year Lag”

This is critical to understand: The GRP data is not real-time.

New ISBN assignments can take 12-18 months or longer to appear in the global database. This delay occurs because:

National ISBN agencies report data to the International ISBN Agency periodically
The data goes through a verification and integration process
Updates are released in batches

If a new publisher doesn’t appear in the GRP, it doesn’t mean they’re illegitimate—it might just mean they haven’t been integrated into the global database yet.

Incomplete Records

Some smaller publishers or self-publishing authors may have minimal records. The depth of information varies by country and agency.

No Real-Time Updates

You cannot use the GRP to verify a book that was published yesterday. It’s a historical record, not a live database.

Practical Use Cases

For Authors

Verify that your publisher has properly registered your ISBNs
Research competing publishers’ imprints
Confirm your own publisher name appears correctly before distribution

For Librarians

Validate cataloging information
Verify publication sources for acquisition decisions
Identify the correct publisher for interlibrary loan requests

For Book Retailers

Confirm publisher details for ordering systems
Verify legitimate suppliers
Research titles for inventory decisions

How to Search Effectively

By ISBN Prefix

The first 3-7 digits of an ISBN identify the publisher prefix. For example:

978-0-13 → Pearson Education
978-0-06 → HarperCollins
978-81-xxx → Indian publishers

By Publisher Name

Search the registered legal name—imprints may be listed separately.

By Country

Some search interfaces let you filter by country/region.

Conclusion

The ISBN Registrant Database (Global Register of Publishers) is an essential tool for anyone working in book publishing. Whether you’re verifying a publisher’s legitimacy, researching competitors, or ensuring your own ISBNs are properly registered, the GR dataP provides authoritative.

Just remember its limitations: data lag of a year or more, and varying record completeness. Use it as one tool among many in your research toolkit—not the sole source of truth.

For quick checks, third-party tools like ISBNBarcode.org offer friendlier interfaces. For comprehensive verification, the official portal remains the gold standard.