Long Form Date (Month Name, English) Regex for Go

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching long form date (month name, english), 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

// Long Form Date (Month Name, English)
// ReDoS-safe | RegexVault — Localization > Date Formats

package validation

import "regexp"

var longFormDateMonthNameEnglishRe = regexp.MustCompile(`^(?:((?:[0-2]?[0-9]|3[01])(?:st|nd|rd|th)?)\s+(January|February|March|April|May|June|July|August|September|October|November|December)\s+((?:19|20)[0-9]{2})|(January|February|March|April|May|June|July|August|September|October|November|December)\s+([0-2]?[0-9]|3[01])(?:st|nd|rd|th)?,?\s+((?:19|20)[0-9]{2}))$`)

func ValidateLongFormDateMonthNameEnglish(s string) bool {
    return longFormDateMonthNameEnglishRe.MatchString(s)
}

// Example
// fmt.Println(ValidateLongFormDateMonthNameEnglish("15 January 2024")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Date Formats 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

Matches both UK order (D Month Y) and US order (Month D, Y). The ordinal suffix (st, nd, rd, th) is optional. Month names are case-insensitive. Abbreviated month names (Jan, Feb) require a different pattern.