Thai National ID (บัตรประชาชน) Regex for Java

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching thai national id (บัตรประชาชน), 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

// Thai National ID (บัตรประชาชน)
// ReDoS-safe | RegexVault — Identity & PII > National Identity Numbers

import java.util.regex.Pattern;

public class ThaiNationalIdValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^[1-9][0-9]{12}$");

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

    // Example
    public static void main(String[] args) {
        System.out.println(validate("1234567890123")); // true
    }
}

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > National Identity Numbers 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

Thai ID structure: region (1-8 for citizenship type), province/district/registration sequence (11 digits), check digit. First digit 1-8 = born in Thailand, 0 = illegal immigrant, 9 = not eligible. Checksum: sum of first 12 digits × weights (13-2), last digit = (11 - (sum mod 11)) mod 10.