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Browser-based tool

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

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.

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

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

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.

Encode unsafe URL characters or decode percent-encoded text.

Check JSON syntax and catch parser errors before the payload goes any further.

Check the status of a public URL from the browser and get a quick response summary.

Paste your input at the top and the result shows up right below. The FAQ and related tutorials are there if you want more.

Most tools run entirely in your browser.
Your input isn't sent to a server unless a tool says it makes a network request.
Related tools and tutorials sit below when a task usually needs a follow-up.