JavaScript Regex Tester

Test JavaScript regular expressions with live match highlighting, capture groups, and replacement. Matching runs in a separate browser thread with a short time limit.

Regular expression pattern

Checking pattern…

Quick patterns

Test string

Pattern: 2,000 characters. Test string: 100,000 characters.

Highlighted matches

Hello, World! Contact us at hello@example.com or support@justtools.app. Visit https://justtools.app for free tools. Phone: (555) 123-4567 or 555.987.6543 Today is 2026-04-24. IP: 192.168.1.1 Color: #4f46e5 or #fff

Evaluating in a separate browser thread…