JavaScript Regular Expression (Regex) Tester
Free online JavaScript regex tester. Enter a pattern and flags, paste test text, and see every match with its index and capture groups instantly.
Tool Configuration Options
What is a JavaScript Regular Expression (Regex) Tester?
A regex tester lets you try a regular expression against sample text before you put it in code. This tester uses the JavaScript RegExp engine built into your browser, so results match what you will get in Node.js and front-end code. It lists every match with its position and captured groups, and shows a clear error when the pattern is invalid.
Execution Privacy:Toolbrix processes this utility using🔒 Processed locally — regular expression matching runs inside your browser JavaScript engine.
How to use this JavaScript Regular Expression (Regex) Tester
Enter your pattern in Regex Pattern without the surrounding slashes, for example \d{3}-\d{4}.
Set flags: g for all matches, i for case-insensitive, m for multi-line anchors, s to let . match line breaks.
Paste the text you want to search into the input box.
Read the matches, indexes and groups in the result panel and adjust the pattern until it is right.
Frequently Asked Questions
Q:Which regex flavour does this use?
JavaScript (ECMAScript). Most syntax is shared with PCRE and Python, but some features, such as possessive quantifiers, are not supported.
Q:Why do I only get one match?
Without the g flag a JavaScript regex stops after the first match. Add g to the flags.
Q:How do I match a literal dot or bracket?
Escape it with a backslash: \. matches a dot and \[ matches an opening bracket.
Q:Is my test data uploaded?
No. Matching runs in your browser.
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