Regex Tester

Test regular expressions with live matching, highlighting, and a library of common patterns.

A regular expression (regex) is a sequence of characters that defines a search pattern. For example, \d+ matches one or more digits.
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Paste or type the text you want to search through. Matches will be highlighted in real-time.

Matches

Shows each piece of text that matches your pattern, with its position in the string.
No matches
Email[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
URLhttps?://[^\s]+
Phone\+?[\d\s\-()]{7,}
IP Address\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}
Date (YYYY-MM-DD)\d{4}-\d{2}-\d{2}
Hex Color#[0-9a-fA-F]{3,8}

How to Use the Regex Tester

1

Enter Your Pattern

Type your regular expression pattern in the pattern field. Toggle flags like global (g), case-insensitive (i), or multiline (m) as needed.

2

Add Test Text

Paste or type the text you want to test against in the test string area.

3

View Matches

Matches are highlighted in real-time. See match count, positions, and captured groups below.

Features

Live regex matching with real-time highlighting
Toggle flags: global, case-insensitive, multiline, dotAll
Match count and position display
Replace mode with live preview
Library of common patterns (email, URL, phone, IP, date, hex color)
Detailed error messages for invalid patterns
100% client-side — no data sent to servers
Free to use with no sign-up required

Frequently Asked Questions

This tool uses JavaScript's built-in RegExp engine, which supports standard regex syntax including lookahead, lookbehind, named groups, and Unicode properties.

g (global) finds all matches, i (case-insensitive) ignores case, m (multiline) makes ^ and $ match line boundaries, s (dotAll) makes . match newlines.

Yes. Use parentheses () for capture groups and (?<name>) for named groups. Matched groups are displayed in the results.

Yes. Everything runs in your browser. No regex patterns or test strings are sent to any server.

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