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Text toolsRegex Tester
Test JavaScript regular expressions in an isolated, time-limited worker.
Processed locally in your browser — your data is not uploaded.Loading your tool…
How to use Regex Tester
- Enter a JavaScript regex pattern and flags.
- Add test text and run the isolated matcher.
- Review highlighted matches and capture groups.
Can a regex freeze the page?
Matching runs in a worker that is terminated after 750 milliseconds. Pattern and input sizes are also bounded.
No sign-up is required. The calculation or transformation happens in this browser tab and the result is available immediately.
Good to know
Which flags are supported?+
The standard JavaScript flags d, g, i, m, s, u, v and y are accepted when supported by your browser.
Does this evaluate JavaScript?+
No. It compiles only a RegExp and never runs arbitrary JavaScript.
Is my input uploaded?+
No. Processing happens in this browser tab and the tool does not send your input or result to Metyris.