Regex Tester & Playground
Write a pattern, paste test text and watch matches highlight live — with capture groups, flags and a quick syntax reference.
Runs 100% in your browser — nothing is ever uploaded.
What is Regex Tester?
Test regular expressions live with instant match highlighting, capture groups and flags. Free online regex playground — everything runs in your browser. Paste your content, get an instant result, and copy or download the output with a single click. No installation, no account and no upload: the whole process happens client-side in your browser, which keeps your data 100% private.
How to use Regex Tester
- Open Regex Tester — it loads instantly and needs no sign-up.
- Paste or type your input into the editor (or press Sample to try an example).
- Adjust the available options if needed and press the action button.
- Copy the result with one click or download it as a file.
Frequently asked questions
Is Regex Tester really free?
Yes — Regex Tester is 100% free with no limits, no watermarks and no registration. You can use it as often as you like, on as many files or inputs as you need.
Is my data safe when I use Regex Tester?
Absolutely. Regex Tester runs entirely in your browser using JavaScript — your input is processed on your own device and is never uploaded to any server.
Does Regex Tester work on mobile devices?
Yes. Regex Tester works in any modern browser on desktop, tablet and mobile (Chrome, Firefox, Safari, Edge) — there is no app to install.
Is my code uploaded to a server?
Never. Every CodeKit tool runs entirely in your browser with JavaScript. Your code is processed on your device and never touches a network — it even works offline once the page is loaded.
Are these tools really free?
Yes — 100% free, no sign-up, no limits, no watermarks. We keep the site running with minimal, non-intrusive ads.
Is there a file or size limit?
No hard limit. Because processing happens on your machine, the only constraint is your device’s memory. Files of several megabytes work fine.