HTML Editor
WEBWrite and edit HTML in your browser with syntax highlighting and an instant, sandboxed live preview — free and offline-friendly.
What is the HTML Editor tool?
This HTML editor online lets you paste markup and see it render live — free, with no sign-up and no upload. The source pane is a real code editor with syntax highlighting and line numbers; next to it, a live preview updates the moment you type. The preview runs inside a sandboxed iframe and the markup is sanitized first, so scripts never execute: you can safely test HTML code from any source without it running anything in your page.
One click on Format runs Prettier over your markup, fixing indentation and tag nesting so messy code becomes readable. Building an email? Insert the built-in starter template — a table-based, inline-styled responsive layout of the kind that renders reliably in Gmail, Outlook and Apple Mail — and edit it live to prototype your newsletter before sending. When you are done, copy the HTML to your clipboard or download it as a ready-to-use .html file.
Everything happens on your device: your code never leaves the browser, which makes the editor safe for client work and private projects, and it keeps working offline once the page has loaded. There is nothing to install and no account to create, and the editor is usable on a phone as well as a desktop — a clean, no-setup workspace whether you are prototyping a page, testing a snippet from a tutorial, or learning HTML from scratch.
How to use the HTML Editor
- Paste or type your HTML into the source pane — the live preview renders it instantly.
- Watch the sandboxed preview update as you edit; scripts are stripped, so nothing executes.
- Click Format to clean up indentation and tag nesting with Prettier.
- Insert the email starter template if you are building a newsletter or HTML email.
- Copy the finished HTML or download it as an .html file.
Frequently asked questions
How do I test HTML code online?
Paste the code into the source pane and the preview renders it immediately — no setup, no saving, no local server. Edit anything and the preview follows keystroke by keystroke, which makes it a quick HTML tester for snippets, tutorials and experiments.
How do I test an HTML email?
Insert the email starter template, or paste your own email markup, and check the layout in the live preview. The template uses tables and inline styles — the pattern that renders consistently across Gmail, Outlook and Apple Mail — including a bulletproof call-to-action button you can edit. For final confidence, still send yourself a test message from your email service.
Do scripts run in the preview?
No. The preview is rendered in an iframe with the sandbox attribute and the HTML is sanitized first, so script tags and inline event handlers are stripped before display. You see layout and styling safely, without executing any code.
Is my HTML uploaded anywhere?
No. Editing, previewing, formatting and export all run locally in your browser. Your code never leaves your device, so it stays private and the editor works offline once loaded.
How is this different from the W3Schools Tryit editor or PlayCode?
They are all in-browser HTML playgrounds. Carbide adds a one-click Prettier formatter and an email-ready starter template, keeps the preview sandboxed so scripts never run, and processes everything on your device with no account. Playgrounds like PlayCode focus on running full JS apps — if you need script execution, they are the better fit; for editing, previewing and formatting markup privately, this is.
Is the HTML editor free, and are there limits?
Yes — completely free, with no sign-up, no watermark and no limit on how much HTML you edit, format or download.
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