HTML Preview
Write HTML, CSS, and JavaScript and see a live preview instantly.
Live Preview
HTML Preview — Live HTML, CSS & JavaScript Editor
Write HTML, CSS, and JavaScript directly in the browser and see a live preview instantly. Our free online HTML Preview tool is a lightweight front-end playground — no setup, no account, and no data leaves your device.
What Is an HTML Preview Tool?
An HTML preview tool is an online code editor that lets you write HTML markup, CSS styles, and JavaScript code and immediately see the rendered result. It works like a minimal browser-based IDE for front-end development, perfect for prototyping snippets, testing layouts, learning web development, or debugging small pieces of code.
Unlike full-featured code editors such as CodePen or JSFiddle, this tool is designed to be fast, distraction-free, and privacy-focused. Everything runs locally in your browser — no server processing, no accounts, and no tracking.
How to Use This HTML Preview Tool
Using the tool is simple:
- Write your HTML in the HTML tab. This is the structure of your page — headings, paragraphs, images, links, forms, and any other elements.
- Add your CSS in the CSS tab. Style your HTML with colors, fonts, layouts, animations, and responsive design rules.
- Add JavaScript in the JS tab. Add interactivity, DOM manipulation, event handlers, and dynamic behavior.
- See the live preview update on the right side. By default, auto-run is enabled so every change appears instantly. Disable auto-run and use the Run button for manual control.
- Copy your code using the copy buttons next to each editor tab.
Key Features
| Feature | Benefit |
|---|---|
| Live Preview | See your code rendered in real time as you type |
| Three Editor Tabs | Separate HTML, CSS, and JavaScript editors for clean organization |
| Auto-Run Mode | Preview updates automatically — no need to click Run |
| Manual Run Mode | Control when the preview refreshes for complex scripts |
| Copy Buttons | Copy HTML, CSS, or JS to clipboard with one click |
| Sandboxed Preview | Code runs in a secure iframe — safe for your browser |
| No Account Required | Start coding immediately with zero sign-up friction |
| Privacy-First | All code runs locally — nothing is sent to any server |
Common Use Cases
Quick Front-End Prototyping
Need to test a layout idea, a CSS animation, or a JavaScript snippet? Open the tool, write your code, and see the result immediately. No project setup, no file creation, no build tools required. If you need to format JSON data for your prototype, try our JSON Formatter.
Learning Web Development
HTML, CSS, and JavaScript are the core technologies of the web. This tool gives you a safe sandbox to experiment with tags, selectors, properties, and DOM methods without worrying about breaking anything. Write code, see the result, and iterate quickly.
Debugging CSS Layouts
Sometimes you need to isolate a CSS issue. Paste your HTML structure and CSS rules into the editor, tweak values, and see exactly what changes — without affecting your real project. For checking browser-compatible HTML entities, use our HTML Entity Encoder/Decoder.
Creating Email Templates
Email HTML is notoriously finicky. Write and preview your email markup here, then copy the final HTML into your email service provider. Since the tool uses a sandboxed iframe, you get a clean rendering of your markup.
Testing JavaScript Snippets
Before adding JavaScript to your project, test it in isolation. Write a small function, attach event listeners, and verify the behavior in the live preview. You can also use our Base64 Encoder/Decoder to encode any data your script needs.
Tips for Better Results
- Start with valid HTML. Always include proper tags and nesting. Browsers are forgiving, but clean HTML renders more predictably.
- Use CSS resets for consistent styling. Adding
* { margin: 0; padding: 0; box-sizing: border-box; }at the top of your CSS prevents unexpected spacing. - Test responsive designs. Resize the preview panel or use CSS media queries to see how your layout adapts to different screen sizes.
- Keep JavaScript simple. The preview runs in a sandboxed iframe. Avoid features that require server interaction (AJAX, fetch to external APIs) unless the endpoint supports CORS.
- Use the CSS tab for styles. Avoid inline styles in your HTML — keeping structure and presentation separate makes your code easier to read and maintain.
Frequently Asked Questions
Is this HTML Preview tool free?
Yes. It is completely free, requires no account, and has no usage limits. All processing happens in your browser.
Does the tool support external libraries?
The editor is designed for vanilla HTML, CSS, and JavaScript. You can include external CDN links via <script> or <link> tags in your HTML, but there is no built-in package manager.
Is my code sent to a server?
No. All code runs locally inside a sandboxed iframe in your browser. Nothing is transmitted to any server.
Can I save my work?
The tool does not persist code between sessions. Copy your code to your local files or a code editor before closing the browser tab.
What happens if my JavaScript has errors?
JavaScript errors will appear in your browser's developer console (F12). The preview iframe will still render the HTML and CSS, but the broken script will not execute.