Regex Tester
Test regular expressions with live match highlighting, group capture, and replace preview — all in your browser.
Frequently Asked Questions
How do I test a regular expression online?
Enter your pattern and some sample text, and the tester highlights every match live as you type. It also shows captured groups, so you can confirm your regex works before using it in code.
What do regex flags like g, i and m mean?
g (global) finds all matches instead of just the first, i (ignore case) makes matching case-insensitive, and m (multiline) lets ^ and $ match the start and end of each line rather than the whole string.
What are capture groups?
Capture groups are parts of a pattern wrapped in parentheses. They let you extract specific pieces of a match — for example separating the area code from a phone number — and reuse them in replacements.
Which regex flavour does this use?
It uses JavaScript's regular expression engine, so the syntax matches what you would use in JavaScript and TypeScript. Most patterns also work in other languages, but some advanced features differ.