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UniPreview

UniPreview is a free browser-based tool that lets developers instantly preview code in 23 languages and formats - from HTML, CSS and React to PHP, Python, Vue, Svelte and Markdown. Paste code, pick a language, and see the result immediately. No setup, no login, no cost.

by UNIZUNE Developer Tools Version 1.0.0 Updated
Free First-party app Web Apps
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Overview of UniPreview

What is UniPreview?

UniPreview is a free, multi-language live code preview tool that runs entirely in your browser. Paste or write code, pick a language, and see the rendered result instantly - no account, no install, no server setup.

Supported languages

UniPreview supports 23 languages and formats: HTML, CSS, JavaScript, TypeScript, React (JSX/TSX), Vue 3 (SFC), Svelte, SCSS, Sass, LESS, Pug, Python, PHP, SQL, JSON, Markdown, XML, YAML, Dart, Flutter, Angular and XAML, plus a plain-text fallback. HTML, CSS, JavaScript, TypeScript, the frameworks, and the data/markup formats render inline. PHP runs via php-wasm and Python via Pyodide - both WebAssembly, both in your browser, not on a server. Dart, Flutter and Angular open as an opt-in external preview (DartPad, Zapp or StackBlitz); XAML is shown with syntax highlighting alongside them.

Privacy

Code for every inline language runs locally on your device and is never uploaded. External previews are opt-in: turning them on for Dart, Flutter or Angular sends that code to DartPad, Zapp or StackBlitz to compile.

Sharing and device preview

Share a project with a URL (your code is encoded in the link) or a QR code, and preview how it looks on desktop, tablet and mobile breakpoints before you ship it.

Features

  • 23 languages and formats

    Live or compiled preview for HTML, CSS, JavaScript, TypeScript, React JSX/TSX, Vue 3, Svelte, SCSS, Sass, LESS, Pug, Python, PHP, SQL, JSON, Markdown, XML, YAML, Dart, Flutter, Angular and XAML.

  • Runs in your browser

    HTML, CSS and JavaScript render inline; PHP runs via php-wasm and Python via Pyodide - both WebAssembly, nothing sent to a server.

  • React, Vue and Svelte support

    Preview JSX, TSX, Vue single-file components and Svelte components without a build step.

  • Tailwind-aware HTML preview

    Tailwind utility classes in HTML/JSX are detected and rendered automatically via the Tailwind CDN build.

  • External preview for Dart, Flutter and Angular

    Opt in to run these in DartPad, Zapp or StackBlitz when a full compiler is needed.

  • Device preview mode

    Check layouts at Desktop, Tablet (768x1024) and Mobile sizes, plus a custom size and zoom.

  • URL and QR code sharing

    Share a project as a link or a QR code; very large projects use the link instead of a QR code.

  • Embed and PWA support

    Generate an embeddable snippet, or install UniPreview as a PWA to keep editing offline.

  • 100% free

    No account, no paywalled features, no usage limits.

Screenshots and videos

  • Explore UniSoftware’s modern online code editor with live preview, multiple programming languages, and a clean developer-friendly interface.

  • UniSoftware Online Code Editor with Instant Live Preview for HTML, CSS, JavaScript, and React.

Download UniPreview

These buttons send you to the developer's official site. We never host files or link to unofficial mirrors.

Use in your browserLaunch the web app, no install

Frequently asked questions

What is UniPreview?

UniPreview is a free online code editor with live preview. You can paste or write code in 23 languages and formats and instantly see the result in your browser - no installation or signup required.

Which programming languages does UniPreview support?

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 and XAML, plus a plain-text fallback.

Is my code sent to a server?

No, not for inline languages. 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.

Can I run Python or PHP code online with UniPreview?

Yes. Python runs entirely in your browser using Pyodide (WebAssembly), and PHP runs using php-wasm, a WebAssembly build of PHP. No server or backend is involved.

Can I preview Dart, Flutter or Angular code?

Yes. These 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 once you opt in to external previews in Settings.

Is UniPreview really free?

Yes. UniPreview is free to use with no account, no paywalled features, and no usage limits.

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