HTML Viewer

Open this page, then either choose the file with Open file, drag it onto the viewer, or paste its code into the editor. The page renders beside the code straight away, and it re-renders as you edit, so you can change a heading or a colour and watch the result. Switch between phone, tablet and desktop widths to see how the layout holds up on each, and use Full screen when you want to read the page rather than inspect it. Nothing needs installing and there is no account to make. When you are done, Copy and Download give you the code back, including anything you changed.

No. The file is read by your own browser and rendered inside this page; it is not sent to pagegoat or to anyone else, and nothing is kept once you close the tab. That is the point of doing it this way — a report with a client's figures in it, or a page an AI assistant wrote from your notes, can be checked without handing it to a third party first. The only time a document leaves your browser is if you choose Get a free link, which puts it online as a short-lived public link, or the paid upload, which needs you to sign in. Until then the viewer is just your browser, showing you a file you already had.

Safer here than opening it directly, though not risk-free anywhere. The preview runs in a sandboxed frame with its own locked-down origin, so scripts in the file can run but cannot read this site's cookies or storage, and cannot take over the page around them. What a sandbox cannot do is make the content trustworthy. The file can still load images and scripts from the internet, which tells whoever hosts them that it was opened, and it can still display a login form that asks for a password. Treat an HTML file from someone you don't know the way you would treat a link from them: look, but do not type credentials into it.

Because the page is looking for other files that did not come with it. A single HTML file often refers to a stylesheet, images or scripts by a relative path such as images/logo.png, and those files live in a folder on the sender's computer rather than inside the document. The viewer only has the one file you opened, so anything referenced that way cannot load; anything referenced by a full https address, or written inline inside the HTML, will. If you are the one sending it, either inline the styles and images before sending, or put the whole folder in a ZIP with an index.html at the top — that is the shape a host can serve with everything in place.

Yes. Scripts inside the document run, buttons respond, alerts appear and forms can be filled in, because a page that only half-works is not much use when you are checking it. They run inside the sandbox described above, so a script can change its own page but not this one. Scripts loaded from a full web address, such as a charting library from a CDN, load normally as long as you are online. A few things behave differently from a page on a real website — anything that depends on the page's own address, such as reading its URL or calling back to the server it came from, has no server behind it here.

Choose Phone above the preview. The page is redrawn in a frame 390 pixels wide, which is the width of a typical modern phone held upright, so a layout that only works on a wide screen shows the problem immediately — text running off the edge, columns that never stack, a table that needs scrolling. Tablet uses 768 pixels. If the page looks like a shrunken desktop site rather than a mobile layout at those widths, the usual cause is a missing viewport tag: a line in the head reading meta name viewport with width=device-width, initial-scale=1. Add it in the editor and the preview updates as you type.

On a laptop, double-clicking an HTML file usually works and opens it in your browser. The viewer earns its place in three situations that does not cover. On a phone, an HTML attachment often opens as code, as a plain preview with the scripts stripped out, or not at all. When the HTML is text rather than a file — something an assistant wrote in a chat, or a snippet from an email — there is nothing to double-click until you save it. And when you want to check the page at phone width, or fix something in it and see the result, a browser tab gives you neither. The viewer does all three in one place.

Send a link rather than the file. An attachment makes every recipient solve the problem this page exists for, and it cannot be updated once it has been sent. Put the file on a host and send the address instead: GitHub Pages, Netlify and Cloudflare Pages are free for public pages, and host an HTML file online compares every option honestly. Pagegoat is the choice when the page should not be public — you can put it behind a password, limit it to people you name, or ask each visitor for their email — and when you want readers' comments pinned to the words they are about. For a page someone only needs to see today, Get a free link under the viewer makes a short-lived public link with no account. Links that last start at $2.99 a month.