Regex Tester

JavaScript's built-in RegExp — identical to what runs in Node, browsers, and most web tooling. If your pattern is destined for Python, Go, or PCRE, the core syntax carries over but a few features differ (lookbehind support varies, named-group syntax differs), so verify edge cases in the target language.

g (global) finds all matches instead of stopping at the first; i ignores case; m makes ^ and $ match at every line break instead of only the string's ends; s makes the dot match newlines too. This tester always searches globally for display purposes and shows your chosen flags in the pattern readout.

Usually greedy quantifiers: .* grabs as much as possible, so <.*> swallows from the first < to the last >. Make it lazy with .*? or, better, use a negated class like <[^>]*> which can't cross a closing bracket. The live highlighting makes this instantly visible.

Parentheses capture the text they match into numbered groups ($1, $2…) for extraction or replacement. The results table shows each match's groups separately. Use (?:…) when you need grouping for alternation or quantifiers but don't want a capture.