The file downloads but shows code — why?

Your device opened it as plain text instead of running it. That happens when the app you opened it in is a text or code viewer, not a browser. Open it in a browser and it renders as a page. Or push it to Drafty and share the link, which always renders.

Why does it look broken in the email preview?

Email and chat previews show a thumbnail or a code snippet, not a live web page — they can't run the HTML. A Drafty link is different: it unfurls with the page title and a preview image in Slack, X, and Notion, and opens as the real page when clicked.

How do I open it on my phone?

A raw .html file usually won't open on a phone — there's no browser-friendly way to launch it from a download. A Drafty link does open on any phone browser, since it's a normal web page at drafty.im/canvas/ .

Will the page keep its styling on Drafty?

Yes. An HTML canvas renders as a full standalone page that keeps the author's own styles, and it can run interactive scripts in a sandbox. Markdown canvases render as clean, styled prose instead.

Updated June 8, 2026

Why won't my Claude HTML file open or render?

Quick answer

A file Claude gives you as .html is a standalone web page. It opens in a browser, but not inside Slack, email previews, or most phones. Share it as a Drafty link and it opens everywhere, with no download.

A file Claude gives you as .html is a standalone web page. It opens in a browser, but not inside Slack, an email preview, or most phones. Nothing is broken — those places can't run HTML, so they show a thumbnail or the raw code instead.

The fix is to turn the file into a link. Push it to Drafty and you get a page at drafty.im/canvas/<slug> that opens in any browser, on any device, with no download.

What the .html file actually is

An HTML file is the source for a web page. A browser reads that source and paints the page — the headings, layout, images, and any scripts. Open the same file in a text editor or a code viewer and you see the source itself, the tags and brackets, not the finished page.

So the file is correct. Whether you see a page or a wall of code depends entirely on what opens it.

Why Slack, email, and phones won't preview it

Slack, email clients, and phone file viewers don't run HTML. When you attach an .html file, they fall back to what they can do: show a generic file icon, a code snippet, or a "can't preview this" message. None of that means the file is damaged.

Phones are the sharpest case. Most phones have no clean way to launch a downloaded .html file, so a teammate on their phone often can't open it at all.

How to view it yourself

To see the page the way Claude built it, open the file in a browser.

Find the .html file Claude saved.
Right-click it and choose "Open with," then pick your browser — Chrome, Safari, or Edge.
The page renders, styles and all.

That works for you on your own computer. It doesn't help the people you send it to, which is the next part.

How to share it so it opens for everyone

Publish the file as a Drafty canvas. The canvas is a real web page at a link, so it opens for anyone — desktop or phone — without a download.

Push the file with the CLI: drafty canvas push report.html. Drafty reads the file and renders it as a full page that keeps the styles Claude wrote. Add --title "Q3 report" to set the title.
Or ask Claude to "drafty this file" — same result, no commands to remember.
Share the link. It unfurls with a title and preview image in Slack, X, and Notion, and anyone who opens it can leave comments anchored to the exact element.

Don't have the CLI yet? Grab it from the get page, then push your first file.

Create your first canvas

Frequently asked

The file downloads but shows code — why?: Your device opened it as plain text instead of running it. That happens when the app you opened it in is a text or code viewer, not a browser. Open it in a browser and it renders as a page. Or push it to Drafty and share the link, which always renders.
Why does it look broken in the email preview?: Email and chat previews show a thumbnail or a code snippet, not a live web page — they can't run the HTML. A Drafty link is different: it unfurls with the page title and a preview image in Slack, X, and Notion, and opens as the real page when clicked.
How do I open it on my phone?: A raw .html file usually won't open on a phone — there's no browser-friendly way to launch it from a download. A Drafty link does open on any phone browser, since it's a normal web page at drafty.im/canvas/<slug>.
Will the page keep its styling on Drafty?: Yes. An HTML canvas renders as a full standalone page that keeps the author's own styles, and it can run interactive scripts in a sandbox. Markdown canvases render as clean, styled prose instead.