Text Tools
About the Regex Tester
The Regex Tester runs a JavaScript regular expression against your text and highlights every match live, lists capture groups for each match and previews a replacement. Flags like g, i, m, s and u are supported.
- Category
- Text Tools
- Price
- Free
- Account
- Not required
- Runs
- Entirely in your browser
How to use the Regex Tester
- Enter a regular expression pattern and flags.
- Paste the test text — matches highlight as you type.
- Inspect capture groups, or enter a replacement string (use $1, $2 for groups) to preview the result.
Privacy
Everything runs in your browser: what you type or paste is processed by JavaScript on your device, not on a server. If you are signed out, nothing is saved at all. If you sign in with Google, your inputs and settings are saved privately to your account so they sync across devices.
Frequently asked questions
Is the Regex Tester free?
Yes. Regex Tester is completely free with no sign-up, no usage limits and no watermarks.
Is my data private?
Yes. The Regex Tester processes everything in your browser. Signed out, nothing is saved; signed in, your inputs sync privately to your own account.
Which regex flavor does this use?
It uses the JavaScript (ECMAScript) regex engine built into your browser, including lookbehind, named groups and Unicode property escapes in modern browsers.
How do I reference a capture group in the replacement?
Use $1, $2 and so on for numbered groups, $<name> for named groups and $& for the whole match.
Does it work on my phone?
Yes. Toolbench runs in any modern browser on desktop, tablet or phone — there is nothing to install.
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