Regex Tester - Test Regular Expressions Online
Test your regular expressions in real-time. See matches highlighted, view capture groups, and debug your regex patterns with instant feedback.
Understanding This Tool
What It Does
Test and debug regular expressions with live matching against your test strings. See exactly which parts of your text match the regex pattern in real-time.
Understanding the Results
- Pattern: The regular expression being tested
- Test String: The text being matched against
- Matches: Highlighted portions of text that match the pattern
- Match Groups: Captured subsets within the overall match
- Match Count: Number of matches found
- Replacement: Result of applying replacements
Common Use Cases
- Pattern Development: Develop and test regex patterns interactively
- Text Processing: Extract data matching specific patterns
- Validation: Check if strings match required formats
- Data Cleaning: Replace or modify text matching patterns
- Log Analysis: Extract relevant information from log files
Pro Tips & Best Practices
- Common Patterns: Email, phone numbers, URLs, dates all have standard regex
- Flags: Case-insensitive, global, and multiline flags change behavior
- Escaping: Special characters like . and * need escaping in patterns
Last reviewed:
How this tool works: This tool runs in your browser and on our server in real time. Depending on the tool, results are computed directly from the input you provide or retrieved from live, authoritative data sources at the moment you run a lookup. We do not sell your data, and your lookups are kept private — any history shown here is stored only on your device.