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Installable PWA — works offline, read-only

cnvs.app ships as an installable Progressive Web App. Add it to your home screen or dock; every board you've opened while online stays readable offline. Browse cached boards, pan, zoom and switch between them via the recent-boards sidebar — even on a plane.

Open cnvs.app to install →

How to install

Chrome / Edge (desktop)

Open cnvs.app, click the install icon in the address bar (or three-dot menu → Install cnvs.app). The app opens in its own window with no browser chrome.

iOS Safari

Share menu → "Add to Home Screen". cnvs.app appears as a standalone app icon.

Android Chrome

Browser shows an "Install app" prompt after first visit. Or three-dot menu → Add to Home screen.

Desktop Linux / macOS

Same as Chrome / Edge — install icon in the address bar.

What works offline

Full read access to every board you've previously opened while online — content cached locally.
Recent boards sidebar for switching between cached boards.
Pan, zoom, select freely on cached boards.
Touch gestures (two-finger pan, pinch zoom) work as normal.
Offline banner appears so it's clear you're disconnected.

What pauses until you reconnect

Edits never silently fail or accumulate stale state offline. All write actions are disabled until the browser online event fires and the WebSocket reconnects:

Drawing strokes, the eraser, undo.
Typing new text, editing existing text, paste of images / URLs.
Colour picker, sticky-note toggle.
New canvas, delete canvas.
Move / resize / duplicate via touch.

The WebSocket auto-reconnects once you're back online — no manual refresh.

What's cached, how

A service worker (/sw.js) precaches the full app shell on install: HTML, JS, CSS, fonts, icons, vendor libraries. Each board you visit is network-first-cached at three URLs: /api/boards/<id> (browser snapshot), /json/<id> (REST snapshot), and /svg-preview/<id> (schematic preview).

The board cache is versionless — shipping new app builds never wipes your offline boards. Deleted boards (server returns 404/410 or you delete from this browser) are evicted from the cache so erased content cannot be revived from a stale snapshot.

Privacy in offline mode

Cached boards live entirely in your browser's Cache Storage — never sent anywhere. Clearing browser data wipes them. Deleting your installed PWA wipes them. Boards deleted on the server are also evicted from the local cache.