US National Provider Identifier (NPI) Regex for Java

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching us national provider identifier (npi), ported and verified for Java. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.

Java Implementation

// US National Provider Identifier (NPI)
// ReDoS-safe | RegexVault — Identity & PII > Health Identifiers

import java.util.regex.Pattern;

public class UsNationalProviderIdentifierNpiValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^[0-9]{10}$");

    public static boolean validate(String input) {
        return PATTERN.matcher(input).matches();
    }

    // Example
    public static void main(String[] args) {
        System.out.println(validate("1234567893")); // true
    }
}

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Health Identifiers category and carries a ReDoS-safe certification. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

NPI is the US healthcare provider identifier under HIPAA. Issued by CMS (Centers for Medicare and Medicaid Services). The last digit is a Luhn check digit (applying the Luhn algorithm with prefix 80840 prepended to the 9-digit base). Type 1 NPI = individual, Type 2 = organization.