HTML Viewer

What the HTML Viewer does

The HTML Viewer is an online HTML editor with a live preview. Paste a snippet or write a full page with HTML, CSS and JavaScript, and the rendered result appears next to the code. It is handy for testing email templates, prototyping layouts, checking copied snippets, learning web basics, or quickly reproducing a bug without creating a project, saving files or starting a local server.

The preview refreshes automatically a moment after you stop typing, so you get a tight feedback loop. If you are working on a heavy page or a script with side effects, switch off auto-run and press Run when you are ready. You can also open or drop an existing .html file, reset to a small sample, copy the source, download it as a standalone .html file, or open it in its own browser tab for full-size testing.

Private and sandboxed

Everything runs locally in your browser. Your code is never uploaded and no account is needed. The preview is rendered inside a sandboxed iframe — and so is the page you open in a new tab: scripts can run, but they are isolated from this site, so they cannot read your drafts, cookies or other site data. That makes it reasonably safe to try untrusted snippets, although you should still avoid pasting code you do not understand that loads third-party resources.

Practical tips

Include a complete document with a doctype, head and body to mimic a real page, or paste only a fragment and let the browser wrap it. Use inline style blocks and script tags to keep the example in one file. External libraries can be loaded through absolute URLs. Remember that relative links and local file paths will not resolve, because the preview has no folder behind it. Your last draft is autosaved locally with a restore option, so an accidental refresh will not lose your work.