pfazzi/isbn is a PHP 7.2+ library for working with International Standard Book Numbers.

From Wikipedia:

The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique.[a][b] Publishers purchase ISBNs from an affiliate of the International ISBN Agency.[1]

An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is ten digits long if assigned before 2007, and thirteen digits long if assigned on or after 1 January 2007. The method of assigning an ISBN is nation-specific and varies between countries, often depending on how large the publishing industry is within a country.

The initial ISBN identification format was devised in 1967, based upon the 9-digit Standard Book Numbering (SBN) created in 1966. The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108 (the 9-digit SBN code can be converted to a 10-digit ISBN by prefixing it with a zero digit "0").

The preferred method of installation is via Packagist and Composer. Run the following command to install the package and add it as a requirement to your project's composer.json:

composer require pfazzi/isbn