Free Regex Tester

Test regular expressions against your text and see every match and group.

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Regex Tester: The Complete Guide

Write a regular expression, set your flags, and test it against any sample text. See every match, its position, and all captured groups — updated as you type.

How to use the Regex Tester

  1. Paste or type your code, text, or data into the input box.
  2. Adjust options such as indent size, dialect, or flags when the tool offers them.
  3. The output updates instantly — copy it to your clipboard or download the file.

Features

  • Live matching as you type
  • Supports g, i, m, s, u flags
  • Shows match index & capture groups
  • Runs locally in your browser

Why use this tool

  • Build and debug patterns safely
  • Understand capture groups
  • Test before using regex in code

What is a regex tester?

A regex tester lets you run a regular expression against sample text and instantly see what it matches. It uses the same JavaScript regular-expression engine your code does, so the results match real behavior — ideal for building, learning, and debugging patterns before you ship them.

Frequently Asked Questions

Which regex flavor is this?

JavaScript (ECMAScript) regular expressions, with the standard flags g (global), i (ignore case), m (multiline), s (dotall), and u (unicode).

How do I see all matches?

Include the g (global) flag — the tester then lists every match, each with its index and any capture groups.

Is it free and private?

Yes — it's 100% free with no signup, and everything runs locally in your browser, so your data is never uploaded to a server.

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