CSS Tools

Working on CSS is rarely a single operation. You format a file to read it, notice the palette has drifted, extract the colours, then validate what you changed — and in most online tools each of those steps means finding another page and pasting again. Here they share one editor: the same input, the same settings, and a history of what you have worked on. The language switcher at the top does the same thing across languages, so HTML, CSS, JavaScript, and JSON all behave identically rather than being four unrelated tools.

Stylesheets are not usually secret, but they are often not yours to upload. Client CSS, an unreleased redesign, a theme under NDA — all of it is code that belongs to someone, and pasting it into a server-side tool means trusting a third party with it. Every transform here runs as JavaScript on your machine, which removes the question entirely: there is no request to inspect, no log to worry about, and the tools keep working if you disconnect from the network after the page loads.

Nine things, all in the same editor. Format and minify are the two you will reach for most — one makes a stylesheet readable, the other makes it small. Sort properties and strip comments tidy a file without changing what it does. Add vendor prefixes for older engines. Validate finds the syntax mistakes that make CSS silently stop applying. The colour and selector extractors give you an inventory of what a stylesheet actually contains. And the live preview shows your rules against a sample page so you can judge the result without leaving the editor.

No. Whatever is in the editor follows you when you move between CSS tools, so you can format a stylesheet, look at its colours, then validate it without pasting three times. Each language keeps its own draft and its own history, so switching to the HTML or JSON tools does not disturb your CSS. History is kept in your browser only, and you can pin entries you want to keep.

No. Every one of these tools runs entirely in your browser using JavaScript. Your stylesheet is never uploaded, never logged, and never sent to any server — you can confirm this by opening your browser devtools Network tab while you work, or by disconnecting from the internet after the page loads and watching everything continue to function. That makes it safe to paste proprietary or client CSS.

For anything you deploy regularly, no — a real pipeline with Lightning CSS or cssnano and an Autoprefixer config will minify and prefix on every build, consistently, using your declared browser support. These tools are for the gaps: a CMS theme field, an email template, a snippet destined for a third-party platform, a stylesheet someone sent you, or a quick check of what a file contains before you decide what to do with it.