Every tool you need for regular expressions

Test, replace, explain and learn regex in seconds, privately. Everything runs right in your browser, so your patterns and data never leave your device.

⚡ Instant, live results 🔒 Private — runs in your browser 👀 Free tester, previews for the rest

Choose a tool to get started

Pick one of our regex tools below. No sign-up required.

Regex Tester Test a pattern live against your text with highlighted matches and groups. Regex Replace Search and replace with backreferences and a live output preview. Regex Explainer Break any regex into a plain-English, token-by-token explanation. Regex Cheatsheet A complete reference of regex syntax, with examples for every token. Pattern Library Ready-to-use patterns for email, URL, IP, dates and more — copy and go.

Why use RegexLab

🔒Private by designTesting, replacing and explaining all happen entirely in your browser. Your patterns and text are never uploaded.

⚡Fast and privateLive results as you type, no queues, no software to install. Just open and use.

🎓Learn as you goThe explainer and cheatsheet turn cryptic patterns into plain English, so you actually understand your regex.

Frequently Asked Questions

Are these regex tools free?

The tester, cheatsheet and pattern library are completely free. Replace and the explainer show part of the result for free; to get the full result, pay once for it or go Premium.

Which regex flavor do you use?

RegexLab uses the JavaScript (ECMAScript) regular-expression engine that runs natively in your browser.

Do I need to create an account?

No account is needed to use the tools. You only go through checkout when you choose to pay once or go Premium.

Is my data safe?

Yes. Everything runs locally in your browser — your patterns and test strings are never sent to a server.

Is there a usage limit?

There’s no daily limit. Everything runs in your browser, so very large inputs depend on your device’s memory.

Can I use it on mobile?

Yes. RegexLab works on any modern browser and can be installed as an app on your phone.