URL with IPv6 Host Regex for Go

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching url with ipv6 host, 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

// URL with IPv6 Host
// ReDoS-safe | RegexVault — Web & Network > URL

package validation

import "regexp"

var urlWithIpv6HostRe = regexp.MustCompile(`^https?://\[[0-9a-fA-F:.]{2,45}\](?::(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}))?(?:/[^\s]*)?$`)

func ValidateUrlWithIpv6Host(s string) bool {
    return urlWithIpv6HostRe.MatchString(s)
}

// Example
// fmt.Println(ValidateUrlWithIpv6Host("http://[::1]/path")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > URL 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 enclosed in [ ] per RFC 2732. The colon in the address would otherwise be misinterpreted as the port separator.