Generic Bearer Token (Authorization Header) Regex for Go

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 Go. 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 Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

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

package validation

import "regexp"

var genericBearerTokenAuthorizationHeaderRe = regexp.MustCompile(`^Bearer\s+([A-Za-z0-9\-._~+/]+=*)$`)

func ValidateGenericBearerTokenAuthorizationHeader(s string) bool {
    return genericBearerTokenAuthorizationHeaderRe.MatchString(s)
}

// Example
// fmt.Println(ValidateGenericBearerTokenAuthorizationHeader("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 Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. 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.).