Question 1

What is UniPreview?

Accepted Answer

UniPreview is a free online code editor with live preview. You can paste or write code in 24 different languages and instantly see the result in your browser — no installation or signup required.

Question 2

Which programming languages does UniPreview support?

Accepted Answer

UniPreview supports HTML, CSS, JavaScript, TypeScript, React (JSX/TSX), Vue 3, Svelte, SCSS, Sass, LESS, Pug, Python, PHP, SQL, JSON, Markdown, XML, YAML, Dart, Flutter, Angular, XAML, and plain text — 24 file types in total.

Question 3

Can I run Python code online with UniPreview?

Accepted Answer

Yes. UniPreview runs Python entirely in your browser using Pyodide (WebAssembly). No server is involved — your code stays private.

Question 4

Can I run PHP code online with UniPreview?

Accepted Answer

Yes. UniPreview runs PHP in your browser using php-wasm — a WebAssembly build of PHP. No server or backend is needed.

Question 5

Is UniPreview free to use?

Accepted Answer

Yes. UniPreview is completely free to use with no account, no paywall, and no usage limits. It runs entirely in your browser.

Question 6

Can I preview Dart, Flutter or Angular code?

Accepted Answer

Yes. Dart, Flutter and Angular need a compiler that can't run in a plain browser frame, so UniPreview shows your code with syntax highlighting and a “Run on DartPad” or “Run on StackBlitz” button. You can also opt in to live embedded previews in Settings.

Question 7

Is my code private?

Accepted Answer

Yes. HTML, CSS, JavaScript, Python, PHP, SQL and every other in-browser language run locally on your device and are never uploaded. Only if you turn on external previews is Dart, Flutter or Angular code sent to DartPad, Zapp or StackBlitz to compile.

Question 8

Can I share my code or use UniPreview offline?

Accepted Answer

Yes. Use Share to create a link that contains your code (compressed into the URL) or an embed snippet, and install UniPreview as a PWA to keep editing offline.