The Single-File HTML App

The single-file HTML app is a small, old idea whose time has quietly come back. No framework to install, no build step, no dependency tree eight thousand nodes deep. Just one file — the way a Word document is one file, or a photograph is one file. You save it, you email it, you put it on a USB stick. Twenty years from now it opens the same way. The App Factory is a workshop for making exactly that kind of file.

Why one file matters

A single file is the smallest possible unit of ownership. You can back it up, hand it down, store it on paper if you like. Nothing depends on a server being up, a framework still being maintained, or a company still existing. If you can open a browser, the app runs.

What lives inside

Everything. Styles are in the same file. Scripts are in the same file. Any images or data get inlined as base64 or embedded as JSON. When you export from the Factory, the file you download is complete — no attachments, no folder of assets, no CDN calls.

The trade-offs, honestly

Single-file apps aren't the right shape for every problem. They can't listen on ports or talk to your database. They're perfect for personal tools, small teams' shared checklists, calculators, journals, planners — anything where "my data on my machine" is the point.

Frequently asked

How big can the file get?

Comfortably a few megabytes. Most personal tools stay well under one MB. Browsers happily load HTML files far larger than that.

Where does my data go?

Into your browser's local storage, in the same file. Export as JSON any time. Nothing is uploaded because there is nowhere to upload it.

Can it work without internet?

Yes. Once the file is on your machine, no network is used. Try it with the Wi-Fi off.

Do I need Node, npm, or a build tool?

No. The Factory itself is one HTML file. The apps you export are one HTML file. There is nothing to install.

One HTML file · MIT-licensed · works offline · nothing to install.

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