HTML Live Preview

HTML preview renders HTML code in real-time, showing exactly how the browser interprets your markup, CSS, and inline JavaScript. This is the fastest way to verify HTML output from template engines, email builders, CMS exports, and code generation tools — paste the HTML and see the rendered result instantly. Unlike opening an HTML file in a browser (which requires saving to disk and refreshing), the AllTools HTML Preview renders content immediately from pasted or typed HTML in a sandboxed iframe. The preview respects all standard CSS styling including external font references, flexbox and grid layouts, media queries for responsive testing, and CSS animations. JavaScript in the HTML executes within the sandboxed preview, enabling interactive component testing. The preview automatically updates as you modify the HTML, creating a live feedback loop for iterative development. This is particularly useful for email HTML development where you need to verify rendering without sending test emails, for CMS template development where the CMS preview may differ from actual rendering, and for static site content blocks where you want to check formatting before committing. All rendering happens locally in your browser.

Email HTML development is one of the most challenging areas of web development — email clients support vastly different subsets of HTML and CSS, and testing requires sending actual emails or using expensive preview services like Litmus or Email on Acid. The AllTools HTML Preview provides an instant first-pass rendering check before engaging those services. Common email HTML patterns you can verify include: table-based layouts (still required for Outlook compatibility), inline CSS styles (since email clients strip style tags), responsive designs using media queries (supported by modern email clients), and image alt text display when images are blocked. Template engine development (Handlebars, EJS, Pug, Liquid, Jinja2) produces HTML output that needs visual verification — the preview shows the rendered output immediately after pasting the generated HTML. Static site development often involves HTML fragments or components that need isolated testing before integration — the preview provides this isolated rendering environment. For educational contexts, the HTML preview helps students see the immediate visual result of their HTML code, accelerating the learning feedback loop.