Free Regex Tester With Live Match Highlighting

A regex that looks correct can still silently fail to match, and debugging it by adding console.log statements to real code is slower than it needs to be. The Regex Tester shows exactly what a pattern matches, live, as you type.

What this tool actually does

• Live match highlighting directly in your test string as you edit the pattern
• Shows capture groups separately so you can confirm extraction logic works as intended
• Supports standard regex flags: global, case-insensitive, multiline
• Instant feedback with no submit button, just type and see results

How to use it, step by step

1. Open the Regex Tester.
2. Type your regular expression pattern.
3. Paste or type test text, matches highlight live.
4. Toggle flags (global, case-insensitive, etc.) and watch the highlighting update.

Why live highlighting beats trial-and-error in code

Rewriting, saving, and re-running a script every time you tweak a regex pattern is slow, especially for patterns with multiple false starts. Seeing matches highlighted instantly turns regex-writing from guesswork into a fast, visual feedback loop.

Common use cases

• Writing a validation pattern for an email or phone number field
• Debugging why an existing regex isn't matching expected input
• Extracting specific substrings using capture groups before writing the extraction code

Frequently asked questions

Which regex flavor does it use?

Standard JavaScript regex syntax, the same engine used in browsers and Node.js, which covers the vast majority of common pattern needs.

Can I test capture groups?

Yes, matched groups are displayed separately from the full match, making it easy to confirm extraction logic before using it in code.

Try it yourself

Next time a regex isn't behaving, test it live on the Regex Tester instead of guessing inside your codebase.