Hosting interactive apps

Published sites can use localStorage, IndexedDB, and the other standard browser storage APIs. Each site runs on its own isolated origin, so anything it stores is private to that site: no other snaphost site can read or change it.

Browser storage lives in each visitor's browser. It is right for per-visitor state: a saved game, a theme choice, a half-finished form. For data you want to keep, see across visitors, or read back later as the owner (guestbooks, leaderboards, RSVPs), use the built-in data backend instead; it needs no setup either.

window.print(), confirm(), and alert() work in published sites, so a "Print this page" button or an "Are you sure?" prompt behaves as expected.

• Storage is per viewing address. Browsers key an embedded site's storage to the address it is viewed on. A visitor who opens the same site on your custom domain and on its snaphost share link gets two separate stores.
• Storage can be cleared. Like everywhere on the web, the browser or the visitor can clear it. Treat it as a cache or a convenience, and keep anything important in the data backend.
• Service workers and offline mode are not supported yet. An app that registers a service worker still runs; the registration itself is what does not take effect.