Regex Tester: Build and Debug Regular Expressions
Test regular expressions against sample text in real time. See matches highlighted, capture groups extracted, and get explanations of your pattern.
What It Does
The Regex Tester evaluates regular expressions against test strings in real time, highlighting all matches and showing capture group contents. It supports JavaScript regex syntax with all flags including global, case-insensitive, multiline, and dotall.
How to Use It
Enter your regex pattern in the pattern field and your test string in the text area. Matches are highlighted instantly as you type. Toggle flags like global (g), case-insensitive (i), and multiline (m). View capture groups in the results panel.
Tips & Tricks
Start with a simple pattern and add complexity incrementally to avoid hard-to-debug regexes. Use named capture groups for clarity in complex patterns. Test edge cases like empty strings, special characters, and very long inputs.
Use Cases
Developers build and debug validation patterns for email, phone, and URL inputs. Data engineers create regex patterns for log parsing and text extraction. Students learn regular expression syntax through interactive experimentation.
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