DEVELOPER TOOL
Regex Tester
Test a regular expression against text and see every match highlighted.
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Match count
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About this tool
Type a regular expression and a block of test text to see every match highlighted live, along with a running match count. Toggle flags like g (global), i (case-insensitive), and m (multiline) to change how the pattern matches.
Matching runs entirely in your browser using JavaScript's native regex engine — nothing is sent anywhere.
Frequently asked questions
- What happens if my pattern is invalid?
- A hint explains what's wrong with the pattern (an unclosed bracket or group, for example) instead of silently showing no matches.
- Why do I need the "g" flag to see all matches?
- Without the global flag, JavaScript's regex engine only reports the first match — the "g" flag tells it to find every occurrence in the text, which is usually what you want when testing a pattern.
- Does this show capture groups?
- The highlighted view shows whole matches. This is aimed at quickly confirming what a pattern matches in context, rather than inspecting individual capture groups.