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Regex Tester

Test JavaScript regular expressions with flags, live matching, and a readable result list.

This uses the browser's JavaScript regex engine. Patterns may behave differently in PCRE, Python, or Ruby.

Pattern Ready

Common regex presets

Flags

Start with one flag at a time. It is easier to diagnose behavior changes that way.

Test text

Matches Match list

FAQ

SEO core content

Is this regex tester free?

Yes.

Which regex engine does it use?

It uses the browser's JavaScript regular expression engine.

Can I test regex flags?

Yes. Add flags like `g`, `i`, `m`, `s`, `u`, or `y` and watch how the result changes.

Why is my regex valid elsewhere but not here?

Regex syntax differs by language and engine. A pattern that works in PCRE or Python may not work the same way in JavaScript.

How To Use It

Search-friendly educational copy

Build regex iteratively

Start with the smallest pattern that matches the basic shape, then add anchors, groups, or flags one step at a time.

That is usually faster than trying to land the perfect regex in one shot.

Watch for engine differences

This tester uses the browser's JavaScript regex engine, so patterns may behave differently in Python, Ruby, or PCRE.

If the regex is heading into another runtime, re-check the advanced parts there before you trust the result.

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What to expect

Built for quick, low-friction checks

These pages are meant to stay direct: input at the top, results immediately below, then the FAQ and related guides if you need more context.

Most tools work entirely in the browser.
Inputs are not sent to a custom backend unless a tool clearly says it makes a network request.
Related tools and short guides are included below when the task usually needs a follow-up step.