watchOS

How do Foundation Models run on Apple Watch?

• Foundation Models on watchOS do not run directly on the device. They require a network connection to a language model provider, such as Private Cloud Compute (PCC) or other conforming protocols.
• FM on watch does not relay through the iPhone's on-device model — it uses the network directly.
• Official support for Claude and Gemini is expected soon.
• Developers can conform to the LanguageModel protocol themselves.
• Use cases include summarizing text for the watch display and making dense text more accessible.

What are the considerations for using Foundation Models on watchOS, especially regarding network connectivity?

• Developers must check if Foundation Models are available before making calls.
• Using PCC requires a specific entitlement.
• Plan for fallback scenarios, such as reaching API quotas or token usage limits with language model providers.
• Network latency is a factor, so carefully consider the timing and frequency of model calls.

What are the core architectural paradigms and pitfalls for iOS developers moving to watchOS, especially for heavy off-main thread work like CloudKit syncing?

• Many familiar APIs like URLSession and CloudKit work on watchOS.
• Swift Async can be used for off-main thread work.
• The system enforces strict limits to preserve battery life and runtime, leading to watchdog timeouts.
• Developers should be mindful of the watch's lower core count and performance constraints compared to iOS.
• Focus on designing experiences tailored for the wrist, prioritizing glanceability, conciseness, and immediate interaction.

What are unique opportunities for developers on watchOS, beyond building a full watch app?

• Live Activities: These appear on the lock screen and can be customized for the Smart Stack without needing a separate watch app.
• Controls: Developers can add controls to the watchOS Control Center, which can be automatically surfaced if they are present in the iOS app.
• These system experiences offer a lightweight entry point to the platform and provide personal, immediate interactions.

What are the recommended modern ways to render 3D graphics on watchOS now that SceneKit is deprecated and RealityKit is not available?

• While SceneKit is deprecated, it can still be used.
• The recommended modern approach is to use SwiftUI Canvas.
• SwiftUI Canvas is a well-featured graphics library suitable for the watch platform and runs on the GPU for performance.
• Developers should consider transitioning away from SceneKit for watchOS development towards SwiftUI Canvas.

What are some underutilized capabilities of watchOS that developers might not know about, encouraging them to extend their apps to the device?

• CoreMotion Sensor Data: Developers can track device motion for novel experiences, such as a tennis game using watch sensors as a peripheral for visionOS, or tracking hand steadiness for activities like pottery.
• Proactive Experiences: Leverage system features like Live Activities and the Smart Stack to proactively deliver timely information and actions to users based on their real-world context (location, time, semantic locations like "at work").
• Widget Suggestions: Associate widgets with specific contexts to ensure they are relevant to the user's current situation.
• Be judicious about surfacing content to avoid users dismissing the app if it appears too often.

What are the key considerations for designing effective Live Activities and Smart Stack widgets on watchOS?

• Relevance: Ensure content is highly relevant to the user's real-world context (location, time, activity).
• Timeliness: Surface information when it's most useful and avoid occupying prime real estate for extended periods.
• Alerting vs. Passive Updates: Differentiate between critical alerts (e.g., delivery arrived) and passive status updates.
• Noise suggestion: Use softer reminders before full alerts when appropriate (e.g., a gentle nudge before a sports score alert).
• Smart Stack Suggestions: Use suggestions for softer reminders or when an alert isn't immediately necessary but the information is still valuable.
• User Dismissal: Design experiences that users can easily dismiss once the information is no longer needed.

What's new for Liquid Glass on watchOS in version 27?

• Refinements include updated visuals with darker edges and speculars for better content separation and legibility.
• Significant performance improvements have been made.
• Interactive glass experiences, like dragging buttons, are now available and fun to use.
• For many apps, especially those using the watchOS 10 design language, Liquid Glass updates are automatic.

Do developers need to do anything specific for watchOS 27 to use Liquid Glass effectively?

• For most developers, especially those already using the watchOS 10 design language, no specific actions are required.
• The new Liquid Glass designs and updates are automatically applied.

Are personal settings for Liquid Glass (like tint or clarity) synced from iOS to watchOS, or is there a separate watch-level preference?

• There is no separate watch-level preference for Liquid Glass tint or clarity.
• The design decision was made to preserve legibility on the primarily dark watch interfaces without needing a user-adjustable slider.
• Accessibility features like "Reduced Transparency" and "Increased Contrast" are available on watchOS.

What are some "hidden gems" in watchOS 27?

• Workout Zones API: This API, requested for years, provides flexible and easy-to-use workout zone boundaries for heart rate and cycling power. It includes rich time-in-zone data useful for both real-time tracking and post-workout analysis.
• Reorderable API: New in SwiftUI and available on watchOS, this API allows developers to easily implement reorderable collections, used internally for Control Center.

How can developers keep watchOS widgets up to date, and what are the best practices for widget updates?

• General Guidance: No significant new guidance for watchOS 27, but good practices remain. Widgets on the watch face have higher priority than those in the Smart Stack.
• Update Frequency: Expect widgets to update every 15-20 minutes if actively used. Smart Stack widgets update based on user engagement.
• Update Mechanisms:
  • Invalidation: Invalidate widgets from the app when new data is available.
  • Timeline Reload Policy: Set an expiration for the widget's timeline for more deterministic refreshes.
  • APNS-based Refreshes: Available since watchOS 26 for server-pushed updates.
  • Watch Connectivity-based Refreshes: New in watchOS 27, allowing phone-to-watch updates.
• Widget Types:
  • Timeline-based Widgets: Suitable for frequently updating data like weather or calendars.
  • Relevant Configuration: Use when a widget is relevant at specific places or times.
  • Live Activities: Ideal for session-based experiences (e.g., sports games, ride-sharing) with a defined start and end, offering more runtime for updates.
  • Controls: For performing quick actions.
• Documentation: Refer to "Keeping The Widget Up to Date" on the developer website and the Widget Kit Foundations video from WWDC26.
• Feedback: Provide feedback on any unmet needs or friction points.

What are the best practices for optimizing heavy asset fetching on a standalone watchOS app's first launch without relying on Watch Connectivity?

• Bundle Essential Assets: Include critical assets needed for the initial launch directly within the app bundle.
• Provide a Useful Initial Experience: Offer users something to interact with or see immediately, rather than just a spinner, while background downloads occur.
• Prioritize Background Downloads: Utilize background URLSession for fetching non-essential assets after the initial launch.
• Consider Offline Scenarios: Design for situations where the user may not have connectivity on first launch, ensuring a graceful experience.
• Mask Complexity: Craft the user experience to hide the complexities of asset downloading and provide a delightful interaction.

How is physical watchOS debugging done in Xcode 27?

• Xcode 27 improves install and symbol-sync reliability for physical watch debugging.
• Device Hub supports direct Mac-to-Watch connection without routing through the iPhone.
• Use 5 GHz Wi-Fi for best results; corporate networks may block peer-to-peer connections.
• If issues persist, file feedback with logs from the failing session.

What are notable new watchOS 27 features?

• Workout Buddy insights for training guidance.
• Siri AI on Apple Watch — coming but not in beta 1.
• Smart Stack holiday surprises and general widget performance/reliability improvements.