HTML export too large: disable offline HTML support?

[Jollywatt]

I produce quite a few Pluto notebooks which are exported as HTML files. After upgrading Pluto, the size of each notebook file jumped from ~50KB to ~8MB.

This is as expected, described here.

However, ~8MB is totally unacceptable for my use case. Is it possible to export leaner HTML files by default?

[cookesan]

The large file is coming from offline_bundle=true.

In the current code, Pluto.generate_html(...; offline_bundle=false) is the default. When offline_bundle=true, Pluto uses the frontend-dist-offline bundle and inlines assets as data URLs, which is exactly the behavior that makes the export self-contained and much larger.

The UI export link currently asks for:

notebookexport_url={this.export_url("notebookexport", { offline_bundle: "true" })}

so the normal browser export path is intentionally using the offline bundle.

Workarounds:

• Programmatic export: call Pluto.generate_html(notebook; offline_bundle=false) if you are exporting from Julia code.
• Browser/manual export: request /notebookexport?id=<notebook-id> without offline_bundle=true.

That produces a smaller HTML file that depends on CDN-hosted Pluto frontend assets, so it is no longer a fully offline/self-contained export.

[Jollywatt]

Thanks for the workarounds!

Follow up question: Do you think it's worth me making a PR to add a checkbox in the export UI? Or does @fonsp have other plans?

[cookesan]

I cannot speak for @fonsp, but a PR for an explicit export choice looks reasonable to me if it keeps the current offline export as the default.

The backend already has both modes: /notebookexport reads offline_bundle from the query string, and generate_html(...; offline_bundle=false) is the default. The current main export card passes a notebookexport_url built with { offline_bundle: "true" }, while the Pluto.land upload path already receives this.export_url("notebookexport") without that flag. So the missing piece is mostly UI/copy, not a new export backend.

For a low-risk PR, I would frame it as “add a smaller CDN-backed HTML export option” rather than “change the default”:

• default/static HTML export remains offline/self-contained
• optional smaller export omits offline_bundle=true and says that the file depends on CDN-hosted Pluto assets

That gives maintainers a small diff to review and avoids changing existing offline behavior. If there is a different plan, they can steer the wording or placement in review.

[Jollywatt]

I should have looked at the source before offering to make a PR — I am completely out of my depth with the frontend! I can't even find where the download URL is set let alone making it depend on a new checkbox 😅

Please regard this question as a feature request!

[fonsp]

Can you write a bit more about your use case? What makes the 8MB unacceptable?

[Jollywatt]

Sure thing. "Totally unacceptable" is maybe too strong a phrase, but I was surprised by the file size.

I keep a bunch of note files (like this one) in a tracked repository, which doesn't like to track files more than a few megabytes by default, so I started needing to increase the limit.

Additionally, and this is perhaps because I have a low-end laptop, Safari wasn't able to open an 8.9MB pluto notebook I had exported this morning (it kept crashing, and even made the music I was playing stutter) while it worked fine when I used offline_bundle=false. However, I can't replicate this, and it works fine now! Maybe my computer was just pressed for resources.

Either way, since the notebooks are ultimately included in a static site, it doesn't make sense for me to use offline-bundled files.

[fonsp]

I think the Checkbox you suggested makes sense! It should be checked by default and sound like an positive/attractive option, like "Offline-ready", with a "help" button to explain the difference. And the design should be a bit more sleek than in the screenshot.

The design goal is to make sure that most people use this, to benefit from the reproducibility of the feature. Users with specific requirements (like you mentioned) can then download the web version instead, but it should not be the default.