Regex Tester

Test regular expressions against sample text and see all matches highlighted.

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Coming Soon

This tool is being built. Check back soon.

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Regex bugs are painful — test before you ship

There is nothing quite like spending 20 minutes writing a regular expression, running it in production, and watching it match the wrong things. A real-time regex tester lets you validate your pattern against actual data before it matters.

What Regex Tester does

Enter your pattern, set flags (global, case-insensitive, multiline), paste your test text, and see every match highlighted in real time. It shows match count, individual positions, and captured groups.

When you need this

Every developer needs this at some point. Validating email formats, extracting URLs from text, parsing log files, finding patterns in data exports — regex is the right tool for all of it, but it needs testing first.

Tips and gotchas

Special characters like . * + ? and parentheses need to be escaped with a backslash if you want to match them literally. The global flag (g) is usually what you want — without it only the first match is returned.

Frequently Asked Questions

What regex flavor does this use?

JavaScript regex (ECMA-262). Compatible with Node.js, browser JS, and most modern languages with minor syntax differences.

How do I match a literal dot or parenthesis?

Escape it with a backslash: \. for a literal dot, \( for a literal parenthesis.

What flags are available?

g (global), i (case-insensitive), m (multiline — ^ and $ match line boundaries), and s (dotAll — dot matches newlines).

Can I test capture groups?

Yes. The tool shows each match including any captured groups in parentheses.

Is my text sent to a server?

No. Pattern matching runs entirely in your browser using the native JavaScript RegExp engine.