Regex Tester & Visual Debugger

Test, build, and inspect regular expressions with real-time match highlighting and capture groups

🎯 Match Highlighting 🔍 Token Explanation 📚 Common Patterns

/ / gm

Flags: g global i case-insensitive m multiline s dotAll u unicode

📄 Test String

🔄 Substitution (Replace):

No matches found.

. Any character except newline

\d Any digit [0-9]

\w Alphanumeric word character [a-zA-Z0-9_]

\s Whitespace (space, tab, newline)

^ Start of string or line

$ End of string or line

* 0 or more repetitions (greedy)

+ 1 or more repetitions

? 0 or 1 repetition (optional)

{n,m} Between n and m repetitions

(...) Numbered capture group ($1, $2)

(?:...) Non-capturing group

(?=...) Positive lookahead

(?!...) Negative lookahead

Pattern and flags ready to paste into your project: they update automatically as you edit the regex above.

Total Matches: 0

Capture Groups: 0

Execution Time: 0 ms

JavaScript ECMAScript RegEx Engine

💡 What are Regular Expressions (RegEx)?

A regular expression (RegEx) is a sequence of characters defining a search pattern. Widely used across JavaScript, Python, PHP, Java, C#, and Go to validate inputs, parse data, and perform complex text transformations.

🚀 Features of Regex Tester Pro

Instant Match Highlighter: Visually highlights matched substrings and capture groups directly in your test string.
Token-by-Token Explainer: Decodes each regex token with human-readable explanations of quantifiers, classes, and anchors.
Live Replace Tool: Simulate text replacements using capture group references ($1, $2, $&).
Built-in Pattern Library: Includes ready-to-use patterns for emails, URLs, IPs, phones, and passwords.
Ready-to-Use Code: Automatically generates your pattern as a snippet in JavaScript, Python, PHP, Java, C#, Go, and Ruby, ready to paste into your project.

🔒 100% In-Browser Privacy

Your patterns and test strings are processed 100% in your browser. Nothing is ever transmitted to remote servers.

📘 Read the Complete Regular Expressions Guide →