Regex Tester

Provide sample strings that should match, and get a suggested regex pattern.

Regex Flavors

• JavaScript (PCRE-like): Supports lookahead, lookbehind, named groups, and all standard JS flags. This is the default and processes patterns using the browser's native RegExp engine.
• POSIX ERE: Extended Regular Expressions used by grep -E, awk, and sed -E. Character classes like [:alpha:] are translated to Unicode-aware equivalents.

Flags

• g — Global: find all matches, not just the first
• i — Case insensitive matching
• m — Multiline: ^ and $ match line boundaries
• s — Dotall: . matches newline characters
• u — Unicode: treat pattern as Unicode code points

Features

• Real-time matching: Matches are highlighted as you type with alternating colors for adjacent matches
• Match details: Full table showing each match, its capture groups, position, and length
• Replace: Test replacement strings with capture group references ($1, $2)
• Pattern explanation: Human-readable breakdown of each component in your regex
• Generate from examples: Provide sample strings and get a suggested pattern
• Common patterns library: One-click access to frequently used regex patterns

Quick Reference

Common Use Cases

• Validation: Email addresses, phone numbers, passwords
• Extraction: URLs, dates, numbers from text
• Search & Replace: Find and replace patterns in text
• Parsing: Log files, CSV data, structured text