Regex Tester Common templates, live highlight, and replace preview — all in one page

Regular Expression Tester - Powerful Online Regex Debugging Tool

Professional tool for developers, data scientists, and DevOps! Verify, debug, and optimize regular expressions with real-time highlighting, ready-to-use templates, and instant replacement preview.

✨ Core Features of Regex Tester

• Real-Time Highlighting: See match results as you type, with visual group borders
• 15+ Common Templates: Email, URL, IPv4, UUID, date, phone, HEX colors, strong passwords
• Instant Replacement Preview: Supports $1-$9 group references, see results without executing code
• Detailed Match Table: Shows index, length, and content of each match + captured groups
• One-Click Flag Toggle: Supports g (global), i (insensitive), m (multiline), s (dotAll), u (unicode), y (sticky), d (indices)
• 100% Local Processing: Everything runs in your browser, zero data sent to server

🎯 Professional Regex Use Cases

• Web Form Validation: Validate emails, phones, credit cards, postal codes, URLs before submission
• Data Cleaning & Transformation: Normalize formats, remove extra spaces, standardize phone numbers
• Server Log Analysis: Extract IPs, timestamps, HTTP status codes, error messages from log files
• Web Scraping & Data Mining: Extract prices, emails, links, metadata from HTML without complex parsers
• Bulk Text Processing: Search and replace patterns in thousands of files (logs, CSVs, JSONs)
• Testing & Development: Test regex before deploying to production (JavaScript, Python, PHP, Java)
• Syntax Highlighting: Create custom syntax highlighters for editors

💡 Regex Tips & Tricks for Developers

For Beginners:

• Start with Templates: If looking for email/URL/phone, use predefined templates as a base
• Enable «g» Flag (global): Without it, you'll only find the first match
• Use Parentheses () to Capture: Capture groups allow extracting specific parts (e.g.: (\d{4})-(\d{2})-(\d{2}) captures year-month-day)
• Escape Special Characters: . * + ? ^ $ { } [ ] \