Online Regex Tester, Debugger & Cheat Sheet
Test and debug JavaScript / PCRE Regular Expressions in real time. Features live string matching, regex cheat sheet, capture group highlights, and replacement tools.
Key Features
- Real-time regex evaluation against test string input
- Regex flags selector (g - Global, i - Case insensitive, m - Multiline, s - Single line)
- Capture group breakdown table and match indices
- Regex substitution / replacement preview tool
- Built-in Regex Cheat Sheet (email, URL, phone number patterns)
How to Use Regex Tester & Visual Matcher
- Enter your regular expression pattern in the Regex input box.
- Set flags (e.g. /g/i).
- Paste text into the Test String panel.
- Review real-time match highlights, capture groups, and replacement preview.
Frequently Asked Questions
What regular expression engine is used?
It uses the native browser ECMAScript JavaScript Regex engine, supporting lookaheads, lookbehinds, unicode properties, and named capture groups.
Does it include common regex templates like email or phone validation?
Yes, click the Regex Cheat Sheet library to load pre-built regex patterns for emails, URLs, dates, and numbers.
Can I test search-and-replace text substitution?
Yes, type a replacement string (using $1, $2 for capture groups) to preview text substitution live.
Is my test string data sent to external servers?
No, all regex evaluation occurs locally in browser JavaScript.