Base64 URL-Safe (No Padding) Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching base64 url-safe (no padding), ported and verified for Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. 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

// Base64 URL-Safe (No Padding)
// ReDoS-safe | RegexVault — Web & Network > Misc

package validation

import "regexp"

var base64UrlsafeNoPaddingRe = regexp.MustCompile(`^[A-Za-z0-9\-_]+$`)

func ValidateBase64UrlsafeNoPadding(s string) bool {
    return base64UrlsafeNoPaddingRe.MatchString(s)
}

// Example
// fmt.Println(ValidateBase64UrlsafeNoPadding("SGVsbG8")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > Misc 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

Used in JWTs, OAuth tokens, and URL-embedded data. Empty string is excluded here since a zero-length token is semantically invalid in most use cases.