Regex Tester
Test regular expressions
Tool Guide
About This Tool
Regex Tester provides real-time regex matching and replacement with instant result highlighting. Supports full Java Script regex syntax — an essential tool for developers, data engineers, and anyone working with text patterns.
Core Features
1. Live matching: Highlights all matches as you type — no need to click Run.
2. Replacement: Supports regex replacement with capture groups ($1, $2) for complex substitutions.
3. Flags: Supports g (global), i (case-insensitive), m (multiline), and other modifiers.
4. Match stats: Shows total match count, capture group contents, and match positions.
How to Use
Step 1: Enter your regex in the pattern box.
Step 2: Paste the test text below.
Step 3: View highlighted matches; fill in the replacement field for substitution preview.
Use Cases
Data extraction: Extract phone numbers, emails, or IPs from logs, HTML, or text.
Form validation: Debug validation patterns for emails, passwords, and IDs.
Text formatting: Normalize text — fix date formats, remove extra whitespace.
FAQ
Q: Which regex engine does it use?
A: Java Script's built-in Reg Exp engine — supports lookahead, lookbehind, and named groups.
Q: Can I match Chinese characters?
A: Yes — use [\u4e00-\u9fa5] to match CJK characters, or type them directly in the pattern.