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Free Online Regex Tester & Debugger

Test and debug regular expressions online with live match highlighting. Free regex tester with global, case-insensitive, and multiline flag support.

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How to use Free Online Regex Tester & Debugger

1

Enter your regex pattern in the Pattern field

2

Toggle flags: g (global), i (case insensitive), m (multiline)

3

Type or paste the test string

4

See live highlighted matches and match list below

Why use this tool?

Live Testing

See matches update in real-time as you type

Visual Highlighting

All matches highlighted directly in the test string

No Setup

Test regex without writing any code

Free Online Regex Tester & Debugger

Test, debug, and experiment with regular expressions in real-time. See every match highlighted directly in your test string, with a detailed list of matches and capture groups. Supports global (g), case-insensitive (i), and multiline (m) flags. No setup, no sign-in—just paste and test.

Quick How-To Guide

  1. 1Enter your regex pattern in the Pattern field
  2. 2Toggle flags as needed: g (global), i (case-insensitive), m (multiline)
  3. 3Type or paste the test string below
  4. 4See live highlighted matches and match list update instantly
  5. 5Adjust the pattern until you get the results you need

Why use our tool?

Live match highlighting directly in the test string
Detailed match list with character index and capture groups
Toggle g/i/m flags with one click
Real-time error detection with clear messages
Match counter: "3 matches found" summary
100% client-side — regex evaluated in your browser

Frequently Asked Questions

Find answers to common questions about using our tool, its features, and how it handles your data privacy.

A regex is a pattern for matching text. It's used in programming for search, string validation, and text manipulation across all major programming languages.
g = global (find all matches, not just first), i = case-insensitive (match regardless of upper/lowercase), m = multiline (^ and $ match start/end of each line).
Common issues: forgetting to escape special characters (use \. for literal dot), not enabling the global flag, or anchors (^ $) being too restrictive.
Yes! Use parentheses () in your pattern to create capture groups. The match list shows each captured group value for every match found.
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