What This Tool Does
This browser-based regex tester uses JavaScript RegExp syntax, highlights matches in test text, lists match indexes, shows numbered and named capture groups, and previews replacement output.
MV ToolsText tool
JavaScript Regex Tester
Test regular expressions, inspect matches and groups, and preview replacements in your browser.
JavaScript Regex Tester and Replacement Preview
Test JavaScript regular expressions, inspect matches and capture groups, and preview replacement output locally in your browser.
Common Use Cases
- Testing regex patterns against logs, API responses, or text snippets
- Checking numbered and named capture groups before using a pattern in code
- Previewing JavaScript replacement strings such as $1, $&, and $<name>
How Data Is Handled
Regex testing runs locally in your browser. Patterns, test text, and replacement text are not uploaded to the backend.
FAQ
Which regex syntax does this tool use?
It uses JavaScript RegExp syntax, so behavior may differ from PCRE, Python, Java, or other regex engines.
Does it support named capture groups?
Yes. Named groups are shown when the browser supports JavaScript named capture groups.
Is my test text sent to the server?
No. Regex testing runs locally in your browser.