About Regex Tester

Regular expressions (regex) are powerful patterns used for matching text. Our regex tester helps you write, test, and debug regex patterns with real-time feedback, highlighting, and detailed match information including capture groups.

Features

• Real-time pattern matching as you type
• Visual highlighting of matches in test text
• Support for all JavaScript regex flags (g, i, m, s)
• Display of capture groups for each match
• Match position and count information
• Library of common regex patterns
• Error messages for invalid patterns

Regex Flags

• g (global): Find all matches rather than stopping after first match
• i (case insensitive): Match both uppercase and lowercase letters
• m (multiline): ^ and $ match start/end of line, not just start/end of string
• s (dotAll): Dot (.) matches newlines as well

Common Use Cases

• Validation: Email, phone, URL, password validation
• Search & Replace: Find and replace patterns in text
• Data Extraction: Extract specific information from logs or documents
• Input Sanitization: Remove or validate user input
• Text Parsing: Parse structured text formats