HTML Preview
Paste any HTML code and see it rendered instantly. Test email templates, blog snippets, and custom HTML.
Related Tools
How to Use
- Paste Your HTML — Type or paste HTML code into the editor. The code is displayed in a monospace font with syntax-friendly formatting. Use the Format button to auto-indent messy HTML.
- See the Preview — The Preview tab renders your HTML in a sandboxed iframe as you type (300ms debounce). The Source tab shows the escaped HTML code. Stats display tag count, line count, and file size.
- Export — Copy the HTML to clipboard or download as a complete .html file with DOCTYPE and charset. The Format button auto-indents your code for readability.
About HTML Preview
WritePadPro's HTML Preview is a lightweight tool for instantly rendering HTML code in your browser. Paste any HTML — from a simple paragraph to a complex email template — and see it rendered in a sandboxed iframe as you type. No build step, no server, no delay.
Use Cases
- Email template testing — Preview HTML emails before sending. Check that inline styles, table layouts, and images render correctly without sending a test email.
- Blog HTML snippets — Test custom HTML blocks, widgets, or embedded content before pasting into your CMS.
- Learning HTML — Students can write HTML and see results immediately. Experiment with tags, attributes, and styling in real-time.
- Quick prototyping — Rapidly test a layout idea, a CSS animation, or a UI component without setting up a project.
- Code review — Paste HTML from a pull request or code review to see what it actually looks like rendered.
Preview Technology
The preview uses an iframe with the srcdoc attribute. Your HTML is wrapped in a complete HTML document structure (DOCTYPE, head, body) and rendered in an isolated iframe. This means your HTML cannot interact with the WritePadPro page — it runs in its own sandboxed context. The preview updates automatically with a 300ms debounce as you type.
HTML Formatter
The built-in Format button automatically indents your HTML code for readability. It inserts line breaks between tags and applies consistent 2-space indentation based on nesting depth. This is useful for cleaning up minified HTML, formatting code copied from browser DevTools, or tidying up hand-written markup. The formatter handles self-closing tags (br, hr, img, input) correctly without adding extra indentation.
Compared to Code Playground
The Code Playground provides three separate editors for HTML, CSS, and JavaScript with a combined preview and console. This HTML Preview is intentionally simpler — one input, one output. If you just need to preview a chunk of HTML quickly, this tool loads faster and has less interface to navigate. If you need to write CSS and JavaScript separately, use the Playground.
Privacy
All rendering happens locally in your browser via the iframe srcdoc attribute. No server is involved. Your HTML code is not transmitted, stored, or processed externally. The tool works offline once loaded. Safe for proprietary templates, internal code, and confidential content.
Frequently Asked Questions
How is this different from the Code Playground?
The Code Playground has three separate editors for HTML, CSS, and JavaScript with a combined preview. This HTML Preview is simpler — one textarea for HTML only, with instant rendering. Use the Playground for multi-file projects. Use this Preview for quick HTML testing, email template checks, and pasting single HTML snippets.
Can I preview email HTML templates?
Yes. Paste your email HTML (including inline styles, tables, and images) and see it rendered immediately. Email templates rely heavily on inline CSS and table layouts, both of which render correctly in the preview iframe. This is faster than sending test emails to check formatting.
Does the Format button fix my HTML?
The Format button auto-indents your HTML for readability — adding proper line breaks between tags and consistent indentation. It does not fix broken HTML or add missing closing tags. It is a formatting/beautifier tool, not a validator.
Is CSS supported in the preview?
Yes. Inline styles (style attribute) and embedded style tags (<style>...</style>) both work in the preview. External stylesheet links will also work if the URL is accessible. The preview iframe has basic default styling for fonts and tables.
Is JavaScript executed in the preview?
Yes. The preview iframe allows script execution within its sandbox. However, for full HTML + CSS + JS development, we recommend the Code Playground which provides separate editors for each language and a console panel for debugging.
Is my HTML sent to a server?
No. The preview uses an iframe with the srcdoc attribute — your HTML is rendered locally in your browser. Nothing is transmitted to any server. The Format and Copy features also work entirely client-side.