nbview

A client-side Jupyter notebook viewer for public GitHub repos. No server: the browser fetches the .ipynb straight from GitHub and renders it, so there's nothing to crash or queue.

Live at nbview.org

What it does

• Browse any user, org or repo (chizkidd, owner/repo, or a pasted GitHub URL)
• Render .ipynb files: markdown, LaTeX (KaTeX), syntax-highlighted code, text, HTML tables, images, SVG, ANSI-colored tracebacks, progress bars
• Inspired by nbviewer: Jupyter classic typography, Pygments-style Python colors, upright math, and long equations that wrap instead of running off the page
• Open notebooks from any direct .ipynb URL that allows cross-origin reads, from a gist link, or from a local file
• nbviewer links work too: paste one into the box, or just change nbviewer.org to nbview.org in the address bar
• Shareable URLs, e.g. nbview.org/#/github/owner/repo/blob/main/path/to/notebook.ipynb, plus a "Copy link" button on every notebook
• Hide code, download, open in Binder (standard JupyterLab, so widgets work) or Colab
• Light and dark mode, following your system until you pick one

nbview is an independent project and is not affiliated with Project Jupyter or nbviewer.

Folder structure

nbview/
├── index.html           
├── _redirects           nbviewer-style /github, /gist, /url, /urls paths -> /#/... routes (the domain swap)
├── _headers             security headers: strict CSP (no forms, no framing, scripts from this site only)
├── robots.txt           allow all crawlers, points to the sitemap
├── sitemap.xml          the home page
├── .well-known/
│   └── security.txt     how to report a security problem
├── assets/
│   ├── css/style.css
│   ├── js/
│   │   ├── app.js       routing, GitHub fetching, notebook rendering
│   │   └── theme.js     restores light/dark theme before first paint
│   ├── vendor/          marked, DOMPurify, highlight.js, KaTeX, served from this site (no CDN)
│   ├── og-light.png     1200x630 link-preview image (og-dark.png is the dark variant)
│   └── og-dark.png
├── CHANGELOG.md
├── LICENSE
└── README.md

Maintenance

• .well-known/security.txt has an Expires date one year out. Renew it by editing that line (next: 2027-10-07).
• Library versions and licenses are listed in assets/vendor/README.md. Update them by replacing the files there, not by adding a CDN.
• Without robots.txt, Cloudflare Pages answers /robots.txt with the home page, so keep the file.

Deployment

1. Hosted on Cloudflare Pages. Every push to main deploys to nbview.org automatically. There is no build step; the repo is served as-is, and Pages reads _redirects on its own.

To run locally: python -m http.server in this folder, then open http://localhost:8000. The _redirects rule only applies on Cloudflare Pages, not locally.

Limits

• Folder browsing and gists use the GitHub API: 60 requests/hour per IP without a token. Add a no-scope token via the "GitHub token" button for 5,000/hour. Opening notebooks uses raw.githubusercontent.com and doesn't count.
• API responses are cached for 5 minutes in the tab (sessionStorage), so going back to a folder you just viewed doesn't use up the limit.
• JavaScript-based outputs (Plotly, Bokeh, ipywidgets) aren't executed, for safety. Static images, tables and text render normally.
• HTML in notebooks is sanitized: scripts, forms and form controls are removed, and author CSS is limited to colors, borders, fonts and layout (no positioning, no url()), scoped to the cell it came from. Only http and https notebook links are accepted.
• Size limits keep one cell from freezing the tab: notebooks over 10 MB (including local files) ask before opening, outputs over 1 MB sit behind a "Show output" button, code cells over 200 KB are shown without syntax colors, and equations over 4,000 characters or 40 levels of nesting, or beyond the first 2,000 in a notebook, are shown as plain TeX. A cell that fails to render is replaced by a notice with its raw source.
• Public repos only.

See CHANGELOG.md for what changed in each release.