What This Tool Does
Regular expressions (Regex) are extraordinarily powerful for matching text patterns, but writing and debugging complex regex patterns by trial and error is notoriously difficult.
Our Regex Tester & Pattern Debugger provides real-time visual match highlighting, capture group index inspection, regex flag toggles, and replacement substitution previews directly in your browser.
How to use
- 1Step 1: Enter your regular expression pattern into the Regex Pattern field.
- 2Step 2: Toggle flags like 'g' (global), 'i' (case-insensitive), or 'm' (multiline).
- 3Step 3: Paste test text into the Test String input box.
- 4Step 4: Review live match counts, match locations, and capture group breakdowns.
Example Scenarios
Use Case 1:Form Validation: Test email, URL, phone number, and password strength rules.
Use Case 2:Data Scraping: Test pattern extraction rules before deploying web scraper code.
Why It's Useful
Real-Time Highlighting: Match boundaries highlight instantly as you type.
100% Client-Side Privacy: Your test data stays in browser memory.
Tips for Best Results
Remember to escape special characters like `.`, `*`, `+`, `?` with a backslash `\` when matching literals.