Regex Tester

What are Regular Expressions?

Regular expressions (regex) are powerful patterns used to match, search, and replace text. They are supported in virtually every programming language — JavaScript, Python, Java, Go, Rust, C#, PHP, Ruby, and more. Regex is essential for input validation, log parsing, data extraction, and text transformation.

Common Regex Patterns

• \\d — any digit (0-9)
• \\w — any word character (a-z, A-Z, 0-9, _)
• \\s — any whitespace (space, tab, newline)
• [abc] — character class: a, b, or c
• a|b — alternation: a or b
• ^ / $ — start / end of string
• * / + / ? — zero or more / one or more / optional
• \{n,m\} — between n and m repetitions
• (?:...) — non-capturing group
• (?<name>...) — named capturing group

Regex Flags Explained

g (global) — find all matches, not just the first. i (case-insensitive) — ignore case when matching. m (multiline) — ^ and $ match the start/end of each line. s (dotAll) — makes . match newlines too.

Features

• Real-time matching as you type
• Syntax highlighting for matched text
• Match details table with index and length
• Flag toggles (g, i, m, s)
• Preset patterns for common use cases
• 100% client-side — your data never leaves your browser