Developer Tools · Local processing

Regex Tester

Test a JavaScript regular expression and inspect its matches.

Your workspace Nothing to install. No signup.

Text stays in this tab. Up to 200,000 characters; results are not saved automatically.

How to use Regex Tester

Patterns run in a separate worker with a one-second limit to stop catastrophic backtracking from freezing the page. Up to 1,000 matches are shown, with positions and capture groups.

01

Add your input

Enter your text or values in the workspace above.

02

Choose your settings

Review the options and limits before processing.

03

Use your result

Check the output, then save or copy what you need.

Good to know

Does this tool upload my input?

No. This tool processes your input on your device. Its libraries load from this site. Your input is not sent to a processing service.

What should I check before using the result?

Patterns run in a separate worker with a one-second limit to stop catastrophic backtracking from freezing the page. Up to 1,000 matches are shown, with positions and capture groups.

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