Free Online Regex Tester & Debugger

Working with regex? This NerdLevelTech tool helps you test and debug your regular expressions instantly. Just enter your pattern, add flags, and paste test text to see:

Live highlighting of matches in your textCapture groups with detailed resultsJSON output of all matchesPresets for common regex patterns

Regex Pattern & Settings

Regular Expression Pattern

Regex Presets

Regex Flags/g

Globalg

Find all matches rather than stopping after the first match

Ignore Casei

Case-insensitive matching

Multilinem

^ and $ match line boundaries in addition to string boundaries

Dot Alls

The . character matches newline characters

Unicodeu

Enable full Unicode support

Stickyy

Matches only from the lastIndex position

Current flags: /g

Test Text

Results

No matches found

Try adjusting your regex pattern or test text to find matches.

Frequently Asked Questions

What is a regex tester?

A regex tester is a tool that allows you to test regular expression patterns against sample text. It shows you which parts of your text match the pattern, helping you debug and refine your regex.

How do I check if my regex works?

Simply paste your regex pattern into the pattern field, set your flags, and enter test text. The tool will highlight matches in real-time and show detailed results including capture groups.

What are regex flags?

Regex flags modify how the pattern matching works. For example, 'g' finds all matches (global), 'i' ignores case, 'm' enables multiline mode, and 's' makes dot match newlines.

Can I share my regex tests?

Yes! Click the "Share Test" button to generate a URL that contains your regex pattern, flags, and test text. Perfect for collaboration or asking for help on forums.

Free foreverNo account requiredPrivacy-focused

All regex testing happens in your browser. No data is sent to our servers or stored anywhere. Your patterns and test text remain completely private.