Regex Tester

Flags, highlights, capture groups, and pattern snippets.

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Built by Derar Sattouf

Regex Playground

3 matches

Pattern

Highlights

Ada wrote notes. Grace built compilers. Linus wrote kernels.

Matches

#IndexMatchGroups
10Ada-
217Grace-
340Linus-

Cheatsheet

\d digit\w word char\s whitespace^ start$ end. any char+ one or more? optional(...) group[abc] set

What is the Regex Tester?

The Regex Tester is a live playground for JavaScript regular expressions. Type a pattern, set flags such as g, i and m, and see every match highlighted in your test text along with its capture groups. Ready-made snippets for emails, URLs and dates help you start fast and learn how each pattern works.

How to use it

  1. Enter a pattern and choose flags.
  2. Paste the text to test against.
  3. Inspect highlighted matches and capture groups.

Features

  • Live match highlighting
  • Capture group breakdown per match
  • Global, case-insensitive, multiline and other flags
  • Common pattern snippets

Frequently asked questions

Is my text sent to a server?

No. The tool runs entirely in your browser with JavaScript. Your text never leaves your device, nothing is logged, and it keeps working offline once the page has loaded.

Which regex flavor does it use?

It uses the JavaScript (ECMAScript) engine built into your browser, so patterns behave exactly as they will in Node.js and front-end code.

What do the g, i and m flags do?

g finds all matches instead of the first, i ignores letter case, and m makes ^ and $ match at the start and end of each line rather than the whole text.

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Last updated: October 2026 · Built by Derar Sattouf