What3Words Address Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching what3words address, ported and verified for Go. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. 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

// What3Words Address
// ReDoS-safe | RegexVault — Identity & PII > Location PII

package validation

import "regexp"

var what3wordsAddressRe = regexp.MustCompile(`^[a-z]+(?:\.[a-z]+){2}$`)

func ValidateWhat3wordsAddress(s string) bool {
    return what3wordsAddressRe.MatchString(s)
}

// Example
// fmt.Println(ValidateWhat3wordsAddress("filled.count.soap")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Location PII 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

What3Words divides the world into 3m × 3m squares, each with a unique 3-word address. The API is proprietary. Format validation can check the 3-word pattern but validity of the address requires the W3W API. 57 trillion unique combinations globally.