Regex Tester — Real-Time Regular Expression Tool

Regex Pattern

g global i ignoreCase m multiline

Test String

Match Results

Highlight

Enter a pattern and test string to see highlighted matches

Replace

Replacement Result

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What Is a Regex Tester?

A regular expression (regex / RegExp) is a powerful notation for pattern matching in strings. It is used extensively in log analysis, data extraction, validation, text replacement, and countless other programming and web development scenarios.

This tool applies the regex pattern you enter to a test string in real time, letting you instantly check highlighted matches, capture group details, and replacement results.

Key Features

Real-time matching — Simply type a pattern to see matches instantly. Flag toggles (g / i / m) are reflected immediately.
Highlight view — Matched portions of the test string are color-coded for easy visual inspection.
Capture group display — View the contents of parenthesized () capture groups in a table. See the values of back-references like $1, $2 at a glance.
Replacement preview — Enter a replacement string to preview results in real time, including capture group references such as $1 and $2.

Common Regex Patterns

Pattern	Description	Example Match
`\d+`	One or more digits	123, 4567
`[A-Za-z]+`	One or more letters	Hello, World
`\b\w+@\w+\.\w+\b`	Simple email address	user@example.com
`(\d{4})-(\d{2})-(\d{2})`	Date (YYYY-MM-DD)	2026-02-26
`https?://[\w/:%#\$&\?~\.=\+\-]+`	URL	https://example.com/path

Runs Entirely in Your Browser

This tool performs all processing entirely in JavaScript within your browser. No text you enter is ever sent to an external server. You can safely test sensitive log data or source code without any privacy concerns.

No external API calls — works offline too
No data storage or transmission — all input is discarded when you close the page
No account required — just open the URL and start using it

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