Forex Currency Pair Regex for Python

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching forex currency pair, ported and verified for Python. 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 Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# Forex Currency Pair
# ReDoS-safe | RegexVault — Finance > Currency & Money

import re

forex_currency_pair_pattern = re.compile(r'^([A-Z]{3})[/\-]?([A-Z]{3})$')

def validate_forex_currency_pair(value: str) -> bool:
    return bool(forex_currency_pair_pattern.fullmatch(value))

# Example
print(validate_forex_currency_pair("EUR/USD"))  # 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 Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. 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

Capture group 1: base currency, group 2: quote currency. EURUSD means 1 EUR = X USD. The slash separator is convention, not universal. Crypto pairs often omit the slash. Validate each code against ISO 4217.