IPv6 in URL Bracket Notation Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching ipv6 in url bracket notation, 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

// IPv6 in URL Bracket Notation
// ReDoS-safe | RegexVault — Web & Network > IPv6

package validation

import "regexp"

var ipv6InUrlBracketNotationRe = regexp.MustCompile(`^\[(?:[0-9a-fA-F]{0,4}:){2,7}[0-9a-fA-F]{0,4}\]$`)

func ValidateIpv6InUrlBracketNotation(s string) bool {
    return ipv6InUrlBracketNotationRe.MatchString(s)
}

// Example
// fmt.Println(ValidateIpv6InUrlBracketNotation("[2001:db8::1]")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > IPv6 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

IPv6 addresses in URLs must be in square brackets per RFC 2732. This pattern uses a simplified compressed IPv6 match — it accepts the major forms but may allow some technically invalid compressed sequences. For strict validation, pair with full IPv6 validation (net-ipv6-02) after stripping the brackets.