A script a website installs in the browser that runs separately from the page. It caches files so the app opens offline and receives web push messages when the page is closed.
See also: Progressive web app (PWA), Offline mode, Web push
Service worker
A script a website installs in the browser that runs separately from the page. It caches files so the app opens offline and receives web push messages when the page is closed.
Nov 8, 2026
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Progressive web app (PWA)
A website built to behave like an installed app: it has a manifest, can be added to the home screen, opens in its own window and can keep working offline through a service worker. The Waitlist App is a PWA, so there is nothing to download from an app store.
Home screen app
A web app added to a phone or tablet home screen from the browser, using Add to Home Screen or Install. It then opens from its own icon in a full window, like a store app, and receives web push where the device allows it.
Passkey
A passwordless sign-in credential based on the WebAuthn standard, stored on the member's device or password manager and unlocked with Face ID, Touch ID or the device lock. Nothing secret is sent or typed, so a passkey cannot be phished or reused on another site.
QR code
A square barcode that a phone camera reads to open a link or carry a code. Businesses use a join QR code so walk-ins can join the queue from their own phone, and tickets and passes carry a QR code that a scanner checks at entry.
NFC
Near-field communication: a short-range radio standard that lets a phone exchange data with a tag or reader held a few centimetres away. Phones use it for tap-to-pay and for opening a link by tapping an NFC tag.