Regex Tester

What is a regex?

Regular expressions are patterns used to match and validate text.

Common metacharacters

Use ., *, +, ?, [], (), ^, and $ to build robust patterns.

Flags and usage

g for all matches, i for case-insensitive matching, m for multiline anchors, and s for dotAll mode.

Capture groups

Groups can be reused in replacements with $1, $2, and so on.

Useful patterns

Try built-in examples for email, URL, date, postal code, and IP addresses.