Regex Tester & Regular Expression Checker

Regular Expressions Explained

A regular expression (regex) is a pattern that describes a set of strings. Regex is used in every programming language for text search, validation, extraction, and replacement. Learning regex is one of the highest-leverage skills for any developer or data professional.

Regex Quick Reference

• . — Any character except newline
• \d — Digit [0-9] | \w — Word character [A-Za-z0-9_] | \s — Whitespace
• ^ — Start of string/line | $ — End of string/line
• + — One or more | * — Zero or more | ? — Zero or one
• {n,m} — Between n and m repetitions
• (abc) — Capture group | (?:abc) — Non-capturing group
• [abc] — Character class | [^abc] — Negated class
• a|b — Alternation (a or b)

Useful Regex Patterns

• Email: [\w.-]+@[\w.-]+\.\w{2,}
• URL: https?://[\w.-]+(?:/[\w./?=&#%-]*)?
• Phone (US): (\+1[-.\s]?)?\(?\d{3}\)?[-.\s]\d{3}[-.\s]\d{4}
• IPv4: (\d{1,3}\.){3}\d{1,3}
• Hex color: #([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})