Regex Tester

Test regular expressions with live matching.

Pattern
Flags
Test String
Matches
ℹ️ Regex Tester runs entirely client-side using JavaScript's native RegExp. No server API is needed. Here's how to use the same logic in your own code:
Test a regex pattern against a string in JavaScript.
// Client-side regex testing — no API call needed const pattern = "[a-z]+@[a-z]+\\.[a-z]+"; const flags = "gi"; const testString = "Contact us at hello@example.com or info@test.org"; const regex = new RegExp(pattern, flags); const matches = [...testString.matchAll(regex)]; matches.forEach((m, i) => { console.log(`Match ${i+1}: ${m[0]} (index: ${m.index})`); }); // → Match 1: hello@example.com (index: 14) // → Match 2: info@test.org (index: 36)