Bento Slides

Bento puts an entire presentation — the slide data, the viewer, the presenter view and the editor — into a single HTML file. Open it in a browser and it presents. Press Esc and the same file is the editor. Press ⌘S and it rewrites itself in place. There is no install, no account and no server; the browser is the whole runtime.

The deck's content is JSON inside a <script> block, so viewing source shows a readable document rather than a compiled blob. Images and fonts are embedded as data, which is what makes the single-file claim hold up when the deck is mailed around or archived. The pitch the demo makes for that design is longevity: the runtime is pinned inside the file, so a deck opened in ten years renders the way it did when it was written, with no dependency left to rot.

Slides share elements by id, and transitions animate the difference between them — position, size, color and gradients. Charts are live instances rather than images: tooltips work while presenting, scroll or pinch zooms the data, and the same chart element morphs between bar, pie and scatter forms across slides. A table can be edited during a talk and the bars and growth line track it. Decks can carry hidden states that arrow keys skip and only a click reaches, plus button links between scenes, which makes a deck closer to a small interactive document than a linear slideshow. There is an on-canvas path editor and a markdown-as-you-type input mode.

What isn't clear

The showcase is a demo deck, not documentation. It advertises collaboration in its Show HN title, but the demo itself shows nothing about how collaboration works, where shared state lives, or what it needs on the network — which is the one claim that sits awkwardly against "a browser is the whole runtime". No public source repository is linked from the demo, and no license is stated, so whether this is open source is unresolved.

The self-update mechanism is worth knowing about before archiving anything: the file checks a signed manifest at launch and rewrites itself. That is defeatable, and the demo says so, but a document that phones home and modifies itself by default is a different artifact than a static file, and it partly undercuts the open-it-in-ten-years argument.

For those reasons it's on the watchlist rather than in use — the format is appealing but the licensing, the source, and the collaboration story all need to resolve first.

Demo and source of these notes: bento.page/slides. Discussed on Hacker News. No repository, star count or license found.