iOS 16 Live Activities: Tracking Real-Time Events

Live Activities in iOS 16 are interactive, glanceable widgets that display real-time, ongoing events directly on your iPhone’s Lock Screen and Dynamic Island. Unlike standard push notifications that alert you once and disappear into notification history, Live Activities maintain a persistent, dynamic presence. This article explains what Live Activities are, how they function under the hood, and how they present live updates such as rideshare progress, sports scores, food deliveries, and timers.

What Are Live Activities?

Introduced by Apple in iOS 16.1, Live Activities bridge the gap between traditional notifications and full home screen widgets. They are designed for time-sensitive tasks that have a clear start and finish. Instead of sending multiple individual notifications to track progress—such as "Driver assigned," "Driver nearby," and "Driver arrived"—an app can use a single Live Activity that updates dynamically in place.

Where Do Live Activities Appear?

Live Activities adapt to your device and context in two primary locations:

  1. The Lock Screen: On all iPhones running iOS 16.1 or later, Live Activities appear as expanded cards anchored at the bottom of the Lock Screen. They remain visible as long as the event is active, providing key data like progress bars, countdowns, and status indicators without requiring the phone to be unlocked.
  2. The Dynamic Island: On supported devices (iPhone 14 Pro and iPhone 14 Pro Max in iOS 16), Live Activities integrate seamlessly into the pill-shaped cutout at the top of the display. They can appear in a compact view when other tasks are running, a minimal view when multiple activities share the space, or an expanded view when long-pressed by the user.

How Live Activities Display Real-Time Events

Live Activities operate through Apple's ActivityKit framework combined with WidgetKit. They function through a coordinated process:

  • Initiation: The user initiates an action inside a compatible app, such as placing a food order or starting a workout. The app requests permission to launch a Live Activity.
  • Local and Remote Updates: Once active, the data can be updated in two ways:
    • Local App Updates: If the app is active in the background, it can update the Live Activity directly.
    • ActivityKit Push Notifications: When the app is suspended, the developer's server sends low-latency push notifications via the Apple Push Notification service (APNs). These pushes contain lightweight JSON payloads (up to 4 KB) containing the updated state (e.g., current score or driver distance).
  • UI Rendering: The iPhone receives the payload and renders the updated interface locally using predefined SwiftUI templates. This approach conserves battery life and data, as the phone does not need to launch the entire application to refresh the visual display.

Lifespan and Limitations

Live Activities are temporary by design. An active session can run for up to eight hours. After an event concludes or hits the time limit, the activity transitions to an ended state, remaining on the Lock Screen for up to four additional hours (or until dismissed by the user) so the final outcome remains visible.