NSS BG

Features

Working offline

How the app caches itself and the AI models so you can work without internet.

What works offline

After your first visit to NSS Background Remover:

  • The entire app shell (HTML, CSS, JavaScript) is cached locally by the service worker
  • The AI model weights are cached after their first download
  • All processing is done locally in your browser anyway — no server is involved

This means you can fully remove backgrounds without an internet connection.

How it works

NSS registers a service worker that manages three caches:

  1. App shell cache — the HTML, CSS, and JavaScript files that make up the app
  2. Asset cache — icons, fonts, and other static assets
  3. Model cache — the AI model weights (ONNX files from Hugging Face)

On each page load, the service worker checks if the cached version is fresh. If you're offline, it serves the cached version. If you're online, it may fetch updates in the background.

First-time setup

To enable offline mode:

  1. Visit the app once with an internet connection
  2. Wait for the page to fully load (the service worker installs)
  3. If you want offline model support: process at least one image (this triggers the model download)
  4. You're now ready for offline use

Checking offline status

To verify offline mode is working:

  1. Open DevTools → Application → Service Workers
  2. Check the worker is "activated and is running"
  3. In the Network panel, switch to "Offline"
  4. Reload the page — the app should load from cache

What doesn't work offline

  • First-time model downloads (model weights must have been cached during an online session)
  • Any first-time HEIC conversion (the HEIC WASM module must have been cached)
  • The help documentation (if you haven't visited those pages before)
  • Any links to external sites (contact, parent company, etc.)

Updating the app offline

When a new version of NSS is deployed, the service worker fetches the update the next time you're online. The update activates on the next page reload. You won't miss updates — they install automatically.

Installing as an app

For the best offline experience, install NSS as an app on your desktop or home screen. Installed apps launch immediately without a browser tab and work fully offline with a single click.

Troubleshooting offline

If the app doesn't load offline:

  1. Check that the service worker is registered (DevTools → Application → Service Workers)
  2. Try visiting the app once more while online and wait for the "ready to work offline" status
  3. Some browser configurations or privacy extensions block service workers. Try in a clean browser profile.

Related

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