Why does GitHub show my HTML file as code instead of rendering it?

By design. `raw.githubusercontent.com` serves files as `text/plain` with `X-Content-Type-Options: nosniff`, which stops browsers from executing arbitrary HTML and JavaScript hosted on GitHub's domain. It is a security decision, not a missing feature, and it will not change.

Is htmlpreview.github.io a good way to preview HTML from a repo?

It works for small public files and it is genuinely handy. The limits are real: the file must be public, the proxy rewrites and re-fetches relative references so multi-file bundles are fragile, large files and rate limits bite, and there is no access control or review layer of any kind.

How do I share an HTML file from a private repo?

You cannot, through any public preview proxy — they all fetch over the public internet. Publish the file to something with identity-based access instead. Comma takes the HTML (or the folder) and gives it a URL with private, team, email-domain or named-reviewer visibility.

What if my HTML report is a folder, not one file?

Preview proxies handle single files well and directories badly. A bundle upload is the right shape: drop the folder or a zip, the entry `index.html` becomes the report body, sibling files upload as assets, and relative references are rewritten so the drill-down links resolve.

Is GitHub Pages the answer instead?

For a public site, often yes. For a one-off report it is heavy — a branch, a build, a deploy, a public URL — and for anything private it means a paid plan with no comment layer. See the GitHub Pages alternatives comparison.

Rendering HTML from a gist or repo

Everyone hits this once. You have an HTML report in a repo — a coverage summary, a profiling output, a chart your script wrote. You push it, open the link, and GitHub shows you the source code.

That is deliberate. raw.githubusercontent.com serves everything as text/plain with nosniff, precisely so nobody can host executable HTML on a GitHub domain. No repo setting turns it off.

The three usual workarounds, honestly

htmlpreview.github.io

Paste your raw URL after https://htmlpreview.github.io/? and it proxies the file with the right content type, rewriting relative references as it goes. For a single small public file this is the fastest thing available and worth keeping in your bookmarks.

Where it stops:

Public only. The proxy fetches over the internet; a private repo 404s.
Multi-file bundles are fragile. Every relative reference becomes another proxied fetch, and anything the rewriter does not recognise breaks.
Rate limits and size. It is a free community proxy, not infrastructure you can depend on for a link you are pasting into a leadership channel.
No access control, no comments, no versions. It is a viewer.

GitHub Pages

A real answer for a real site: build, deploy, public URL, custom domain. For a single report it is a lot of ceremony, and private Pages is a paid-plan feature with no review layer attached. Full tradeoff in GitHub Pages alternatives.

Commit a screenshot instead

The one everybody actually does. It works, and it destroys every number in the report — nothing is checkable, nothing is searchable, and the interactive chart becomes a picture of a chart. See stop screenshotting reports.

The alternative: publish the file, keep the access rules

If what you want is this HTML, at a URL, for these people, the repo was never the right container. Publishing takes one motion:

Drag the file — or the whole folder, or a zip — into the app, or POST it from a script or an agent over MCP.
Pick visibility: private, team, email-domain-gated, named reviewers, or public. Identity, not a shared password.
Get anchored comment threads on the rendered page, and a revision each time you republish to the same id — so the link in your README never goes stale and never changes.

Scripts run, sandboxed (allow-scripts, no allow-same-origin), which is the same reason GitHub refuses to render your file — except the sandbox is the product's job rather than your repo's problem.

At a glance

Option	Private files	Multi-file bundles	Comments / versions	Setup
Comma	Yes, identity-based	Yes, rewritten	Yes / yes	Drag or one POST
htmlpreview	No	Fragile	No	Paste a URL
GitHub Pages	Paid plans	Yes	No	Branch + deploy
raw.githubusercontent	Token-gated	N/A	No	Renders as text

Checked August 2026. Verify current plans before committing.

How to choose

Quick look at a public single-file demo? htmlpreview, every time.
A site with routes? GitHub Pages, Netlify, or Cloudflare Pages.
A report — private, versioned, and something people should respond to? Publish it: share an HTML report.