Getting Started

UniPreview is a free, browser-based code editor with live preview. Paste or write code, choose a language, and the rendered result appears next to the editor as you type - no install, no account, and no server round-trip for inline languages.

How to use it

1. Go to https://codepreview.unisoftware.app
2. Paste your code, or use "Upload file" / "Open file" to load one from disk
3. Pick a language from the language selector (or let UniPreview auto-detect it)
4. The preview updates live as you type - there is no "Run" button to press

What "live preview" means

For inline languages, UniPreview re-renders automatically after a short debounce as you edit - there is no explicit run step. PHP (via php-wasm) and Python (via Pyodide) also execute inline, both as WebAssembly running on your device rather than on a server.

Browser compatibility

UniPreview works in modern desktop and mobile browsers. It can also be installed as a Progressive Web App (PWA) to keep editing offline.

No account, no install

There is no sign-up and nothing to install - UniPreview runs entirely as a web page. See Supported Languages & Formats for the full list of what you can preview.

Multiple tabs and starter examples

A project is not limited to a single file. Add tabs for related files - for example an HTML tab alongside CSS and JavaScript - and the preview combines them, the same way a real page links separate files together. Tabs can be duplicated, renamed, or closed individually (or all at once), and any tab can be opened in its own full-page preview tab in the browser. If you are starting from a blank editor, use "Insert starter example" to load a working starting point for the current language instead of beginning from nothing.

If something goes wrong

If the editor ever freezes or crashes, the "Clear Data & Reload" option resets saved files locally and fixes most issues. A Help panel and a keyboard shortcuts reference (see Settings & Editor Options) are both one click away from the toolbar.