swiftui-performance

Audit SwiftUI performance with Instruments to reduce expensive view updates.

Updated Apr 19, 2026

Search Tags:#performance #optimization #profiling #diagnostics #swiftui #instruments

Ready to run

npx skills add https://github.com/femitz/flyby --skill swiftui-performance-femitz

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: swiftui-performance
Source: https://github.com/femitz/flyby/tree/main/.agents/skills/swiftui-performance
Command: npx skills add https://github.com/femitz/flyby --skill swiftui-performance-femitz

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Audits and improves SwiftUI runtime performance to reduce slow rendering, janky scrolling, and excessive view updates by guiding you through instrumentation, diagnosis, and remediation.

Core Features & Use Cases

End-to-end performance auditing for SwiftUI apps using Instruments (SwiftUI template, Time Profiler, Hangs).
Guidance on common bottlenecks such as long body evaluations, identity churn, and layout thrash, with practical remediation patterns.
Actionable workflow for measuring, diagnosing, and validating improvements across real devices.

Quick Start

Use a Release build on a real device, profile with the SwiftUI instrument, identify the top red updates, and apply the targeted refactors.

Frequently Asked Questions about swiftui-performance

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I fix janky scrolling and slow rendering in SwiftUI apps?▼

Fix SwiftUI performance issues by profiling a Release build on a real device with the Instruments SwiftUI template to identify red updates, then applying targeted refactors to reduce expensive view body evaluations and frame drops.

What causes excessive view updates and identity churn in SwiftUI?▼

Excessive view updates in SwiftUI are caused by long body evaluations, identity churn, and broad observable dependencies. Remediate these performance bottlenecks by applying precomputation, narrowed dependencies, and stable identities.

How to profile SwiftUI performance using Instruments?▼

Profile SwiftUI performance using the Instruments SwiftUI template, Time Profiler, and Hangs instruments on a Release build. Identify the top red updates to pinpoint slow rendering and apply targeted refactors to validate improvements.

Do I need a real device to diagnose SwiftUI performance issues?▼

Yes, diagnosing SwiftUI performance issues requires a real device. You must use a Release build to accurately measure, diagnose, and validate performance improvements without simulator overhead masking frame drops.

What is the best way to reduce layout thrash and broad observable dependencies in SwiftUI?▼

Reduce layout thrash and broad observable dependencies in SwiftUI by narrowing dependency scopes and applying precomputation patterns. This minimizes unnecessary view updates and stabilizes rendering during scrolling.