About Regex Tester
Regex Tester is an essential development tool for programmers and data analysts who need to work with regular expressions and pattern matching. Regular expressions are powerful but can be notoriously difficult to write correctly and debug when things go wrong. Our tool provides real-time visual feedback that makes it easy to understand exactly what your regex pattern matches and where. Enter your regex pattern using standard JavaScript syntax, then test it against any text with instant highlighting of all matches. Every match is clearly marked in yellow within your test text, showing exactly what portions of your string are being captured. View detailed match information including position indices for each match and any captured groups—essential for debugging complex patterns with multiple capture groups. The common patterns library provides instant access to frequently-used regex templates including email addresses, URLs, phone numbers, dates, IP addresses, hex color codes, HTML tags, strong password validation, uppercase words, and more. Simply click any pattern to insert it into the regex field and see it in action immediately. All standard regex flags are supported via easy checkbox toggles: global (g) to find all matches, ignore case (i) for case-insensitive matching, multiline (m) so ^ and $ match line boundaries, dotAll (s) allowing the dot metacharacter to match newlines, unicode (u) for full unicode support, and sticky (y) to match only at the exact position specified. As you type your regex pattern, the tool provides explanations of what your pattern matches, helping you learn regex syntax and identify mistakes. Invalid patterns show helpful error messages explaining what went wrong, making debugging much faster than trial-and-error in code. All testing happens entirely in your browser using JavaScript—your patterns and test strings are never sent to any server. This makes it safe to test regex with sensitive data like log files, user information, configuration files, or proprietary code. Perfect for developers debugging regex for validation (emails, phone numbers, passwords), data analysts extracting information from log files, backend engineers working with string manipulation, security professionals analyzing patterns in data, and anyone learning regular expressions. Use this tool to quickly test, debug, and perfect your regular expressions before deploying them to production.
Unlike many online tools that require account creation or have hidden costs, Regex Tester is completely free and requires no signup. Simply open the tool and start using it immediately. Your privacy is our priority - all processing happens locally in your browser, and your data is never stored on our servers.
Whether you're a professional, student, or casual user, Regex Tester is designed to be intuitive and efficient. Our tool works seamlessly on desktop computers, tablets, and mobile devices, ensuring you can get your tasks done wherever you are.