Decimal Monetary Amount Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching decimal monetary amount, ported and verified for Go. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. 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

// Decimal Monetary Amount
// ReDoS-safe | RegexVault — Finance > Currency & Money

package validation

import "regexp"

var decimalMonetaryAmountRe = regexp.MustCompile(`^-?(?:(?:[1-9][0-9]{0,2}(?:,[0-9]{3})*)|0)(?:\.[0-9]{1,2})?$`)

func ValidateDecimalMonetaryAmount(s string) bool {
    return decimalMonetaryAmountRe.MatchString(s)
}

// Example
// fmt.Println(ValidateDecimalMonetaryAmount("0")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Currency & Money 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

Enforces comma grouping (1,234 not 1234 with thousands). Strip commas before parsing to float. Allows negative amounts. For amounts without thousand separators, use: ^-?[0-9]+(?:\.[0-9]{1,2})?$