WWDC 2026 - WidgetKit Foundations: A Practical Guide for Developers

What makes a widget worth building Apple frames good widgets around three qualities, and they're worth keeping in your head as design constraints, not just slogans: Glanceable — someone should understand it in a fraction of a second. Think Weather showing you just enough of today's forecast. Relevant — content should match the moment, the place, and the person's patterns. Calendar surfacing your next event is the canonical example. Personalizable — it should be configurable with the content that matters to that specific user. These three map directly onto the technical decisions you'll make: glanceable drives your view design, relevant drives your timeline strategy, and personalizable drives whether you reach for a configurable (App Intent) widget. The mental model: how a widget actually runs This is the part most newcomers get wrong, so it's worth being precise. Your widgets are delivered to the system from a widget extension , which is a separate process from your app. That separation has a real consequence: your app can't just hand data to the extension in memory. You share data through an app group container — a shared database, or UserDefaults backed by the group. Wire this up early; it's the thing people forget. Whether your app is UIKit or SwiftUI, the widgets themselves are always built in SwiftUI. The data flow is: WidgetKit asks your extension for content. That content is a timeline — a series of timeline entries . Each entry carries the data needed to render your view at a specific point in time. The rendered views are archived, and the system displays each one at its relevant time. The key insight hiding in step 4: your code is not running while the widget is on screen. The system renders archived views. This explains a lot of WidgetKit's API design, including why interactive elements use App Intents rather than closures. Building your first widget When you add a widget extension target, Xcode scaffolds most of what you need. The body returns a WidgetCon