Regex Tester
Test and debug regular expressions with real-time matching, detailed analysis, and comprehensive pattern library.
Regex Tester
Test and debug regular expressions
//
Test String
Characters: 0 | Lines: 1
Results (0 matches)
Text with matches highlighted will appear here...
No matches found
Regex Quick Reference
Common Patterns:
- . - Any character (except newline)
- * - 0 or more of preceding
- + - 1 or more of preceding
- ? - 0 or 1 of preceding
- \d - Any digit (0-9)
- \w - Any word character
Character Classes:
- [abc] - Any of a, b, or c
- [a-z] - Any lowercase letter
- [^abc] - Not a, b, or c
- ^ - Start of string/line
- $ - End of string/line
- \b - Word boundary
About Regular Expressions
What are Regular Expressions?
Regular expressions (regex) are powerful patterns used to match character combinations in strings. They're essential for text processing, validation, and search operations.
Common Use Cases:
- • Validation: Email, phone, URL format checking
- • Data Extraction: Parse logs, CSV files, HTML
- • Text Processing: Find and replace operations
- • Input Filtering: Clean user input data
- • Search & Replace: Advanced text manipulation
Tool Features:
- • Real-time Testing: Instant pattern matching
- • Visual Highlighting: See matches in context
- • Flag Support: Global, case-insensitive, multiline
- • Capture Groups: Extract specific parts of matches
- • Common Patterns: Pre-built regex library
- • Error Detection: Clear regex syntax validation
- • File Upload: Test against large text files
- • Match Statistics: Count and position tracking
Quick Reference
Basic Patterns:
- . - Any character
- * - 0 or more
- + - 1 or more
- ? - 0 or 1
- ^ - Start of line
- $ - End of line
Character Classes:
- \d - Any digit
- \w - Word character
- \s - Whitespace
- [abc] - Any of a, b, c
- [a-z] - Any lowercase
- [^abc] - Not a, b, c
Quantifiers:
- {3} - Exactly 3
- {3,} - 3 or more
- {3,5} - Between 3-5
- (abc) - Capture group
- (?:abc) - Non-capture
- \b - Word boundary
💡 Pro Tips:
• Test regex patterns with various inputs
• Use capture groups to extract specific data
• Be careful with greedy vs lazy quantifiers
• Escape special characters when needed