Generic Bearer Token (Authorization Header) Regex for Java

What this pattern does

This page provides a well-structured, multi-part regular expression for matching generic bearer token (authorization header), ported and verified for Java. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. 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

// Generic Bearer Token (Authorization Header)
// ReDoS-safe | RegexVault — Security > API Keys & Tokens

import java.util.regex.Pattern;

public class GenericBearerTokenAuthorizationHeaderValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^Bearer\\s+([A-Za-z0-9\\-._~+/]+=*)$");

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

    // Example
    public static void main(String[] args) {
        System.out.println(validate("Bearer eyJhbGciOiJSUzI1NiJ9.abc.def")); // true
    }
}

Test Cases

When to use this pattern

This pattern is drawn from the Security > API Keys & Tokens 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

RFC 6750 Bearer token format. The token itself is an opaque string — not validated structurally here. The character set covers base64url, standard base64, and common token formats. Use downstream pattern to validate the token type (JWT, opaque, etc.).