Regex Tester & Debugger

Test and debug regular expressions with live match highlighting, capture groups, and flags. Includes common regex reference patterns. Free and client-side.

/ /
Test String
Matches (highlighted)
Matches will be highlighted here...
Match List
No matches yet.
Common Regex Reference
\\d+
Match digits (numbers)
\\w+
Match word characters
[a-zA-Z]+
Match letters only
[^@]+@[^@]+\\.[a-z]+
Simple email pattern
https?://\\S+
Match URLs
\\d{4}-\\d{2}-\\d{2}
Date (YYYY-MM-DD)
\\b\\d{3}-\\d{4}\b
Phone (123-4567)
\\$\\d+(\\.\\d{2})?
Currency amount

About Regex Tester

Our Regex Tester is a free online tool for testing and debugging regular expressions. Whether you're validating input, parsing text, or building complex search patterns, this tool gives you instant visual feedback with match highlighting and capture group inspection.

Key Features

All processing happens in your browser. No data leaves your device.

FAQ

What regex engine does this use?
This tool uses the JavaScript RegExp engine built into your browser, which follows the ECMA-262 specification.
What do the flags mean?
g = global (find all matches), i = case-insensitive, m = multiline (^ and $ match line boundaries), s = dotAll (. matches newlines), u = unicode mode.
How many matches can it find?
The tool caps at 10,000 matches to prevent browser freezing on pathological patterns. Most real-world use cases stay well within this.
Can I use capture groups?
Yes. Capture groups are displayed for each match with their index and captured value.

Related Tools

📋 JSON Formatter
Format, validate, and beautify JSON data
🔐 Base64 Encoder
Encode and decode Base64 strings and files
🔗 URL Encoder
Encode and decode URLs and components
⚡ Text Diff
Compare two text blocks line by line