US National Provider Identifier (NPI) Regex for PHP

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching us national provider identifier (npi), ported and verified for PHP. 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 PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

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

define('US_NATIONAL_PROVIDER_IDENTIFIER_NPI_PATTERN', '/^[0-9]{10}$/');

function validate_us_national_provider_identifier_npi(string $input): bool {
    return (bool) preg_match(US_NATIONAL_PROVIDER_IDENTIFIER_NPI_PATTERN, $input);
}

// Example
var_dump(validate_us_national_provider_identifier_npi("1234567893")); // bool(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 PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. 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.