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Regex101 Lab — free online tool

Go beyond a simple match: see capture groups, try replace patterns, and skim a quick syntax reference for JavaScript regex.

Useful when you want a quick answer without pasting sensitive data into random chat bots.

How to use Regex101 Lab

  1. Enter a regex pattern in the Regex101 Lab pattern box (JavaScript flavour).
  2. Add test text below and view match highlights and groups.
  3. Try replace preview if you are validating substitution syntax.
  4. Open the quick reference section on the page for anchors and quantifiers.

Practical tips

  • Use the replace preview to confirm a substitution before running it on real data.
  • Lean on the quick reference for tokens you forget, like \b word boundaries.
  • Patterns run in your browser with JavaScript regex—no PCRE-only syntax.

Limitations

Regex101 Lab runs on text in your tab only—there is no cloud save, version history, or collaboration. Copy results before closing the page.

Privacy & data

We do not run a database on this static site. Text and generated output exist only in your tab until you close or refresh the page.

Frequently asked questions about Regex101 Lab

Is the Regex101 Lab free on Webtoolshop?

Yes. There is no sign-in and no paywall on this page. We may show advertising on some layouts to cover hosting.

Can I use the Regex101 Lab on a phone?

Yes for light tasks. Very long pasted text, huge images, or multi-megabyte PDFs are easier on a laptop with more memory.

Why did the Regex101 Lab fail or look wrong?

Try a smaller file, fewer pasted characters, or an updated browser. Extensions that block scripts or downloads sometimes interfere—test in a private window if results never appear.

Does Webtoolshop store text I paste into the Regex101 Lab?

We do not run a database on this static site. Text and generated output exist only in your tab until you close or refresh the page.

Regex101-style Lab

JavaScript flavor: matches, groups, and replace preview. For PCRE / full debugger open regex101.com.

Inspired by regex101.com — this page runs regex in your browser only (no PCRE).

Matches

After replace

Quick reference (JavaScript) 
. any char   \d digit   \w word   \s space   ^ $ line bounds
+ * ? {} quantifiers   [] class   () group   | alternation
Use flag g for all matches, i case-insensitive, m multiline, s dotall
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