ISBN

The isbn rule validates that a value is a valid ISBN-10 or ISBN-13, including real checksum verification.

Configuration

validationSchema: {
  book: { isbn: true },
}

With a custom message:

book: { isbn: "Enter a valid ISBN" }

V builder

import { V } from "formify-js";

V.isbn()
V.isbn("Enter a valid ISBN")

Default message

Must be a valid ISBN

Examples

Things to know

• Both formats are verified with their real checksum algorithms — a wrong final digit fails validation.
• Dashes and spaces in the input are tolerated during parsing.
• Empty values pass unless required: true is also set.