Regex Tester
Test and debug regular expressions with live matching
About Regex Tester
Regex Tester is a developer-friendly tool for writing, testing, and debugging regular expressions with instant live feedback. Whether you are validating email addresses, extracting data patterns, or parsing complex strings, this tool helps you get your regex right without the guesswork.
Test your patterns against sample text in real-time, see exactly which parts match, and refine your expressions on the fly. All processing happens locally in your browser, ensuring complete privacy while you work with sensitive data or patterns.
How to use Regex Tester
Enter Your Regex Pattern
Type or paste your regular expression into the pattern field at the top of the tool.
Paste Your Test Text
Enter the text or string you want to test against in the input area below.
Review Matches Instantly
Watch matches highlight in real-time, view capture groups, and copy results as needed.
Pro Tips
- Use the global 'g' flag to find all matches in your text, not just the first one-perfect for batch extraction tasks.
- Test edge cases like empty strings, special characters, and multiline text to ensure your regex handles real-world scenarios.
- Leverage capture groups (parentheses) to extract specific parts of matches-view exactly what was captured in the details panel.
- Start simple and build complexity gradually; test smaller patterns first, then combine them into larger expressions for better debugging.
Key features of Regex Tester
Live Pattern Matching
See matches highlighted in real-time as you type your regex pattern and test string.
Match Groups & Captures
View captured groups and submatches to understand exactly what your pattern extracts.
Regex Flags Support
Toggle global, case-insensitive, multiline, and other flags to customize pattern behavior.
Match Details Panel
Inspect every match with position, length, and captured group information displayed clearly.
Quick Copy Results
Instantly copy your regex pattern, matches, or matched text to clipboard with one click.
Error Detection
Instantly catch syntax errors in your regex with helpful error messages and suggestions.
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