# Swiftui Performance Audit

Audit and improve SwiftUI runtime performance from code review and architecture.

- Repository: https://github.com/Dimillian/Skills (4021 stars)
- Category: Mobile
- License: MIT
- Last updated: 2026-03-29
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add Dimillian/Skills --skill swiftui-performance-audit -g -a claude-code -y`
Codex: `npx skills add Dimillian/Skills --skill swiftui-performance-audit -g -a codex -y`
Cursor: `npx skills add Dimillian/Skills --skill swiftui-performance-audit -g -a cursor -y`
Gemini CLI: `npx skills add Dimillian/Skills --skill swiftui-performance-audit -g -a gemini-cli -y`

## Description

Audit and improve SwiftUI runtime performance from code review and architecture. Use for requests to diagnose slow rendering, janky scrolling, high CPU/memory usage, excessive view updates, or layout thrash in SwiftUI apps, and to provide guidance for user-run Instruments profiling when code review alone is insufficient.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# SwiftUI Performance Audit

## Quick start

Use this skill to diagnose SwiftUI performance issues from code first, then request profiling evidence when code review alone cannot explain the symptoms.

## Workflow

1. Classify the symptom: slow rendering, janky scrolling, high CPU, memory growth, hangs, or excessive view updates.
2. If code is available, start with a code-first review using `references/code-smells.md`.
3. If code is not available, ask for the smallest useful slice: target view, data flow, reproduction steps, and deployment target.
4. If code review is inconclusive or runtime evidence is required, guide the user through profiling with `references/profiling-intake.md`.
5. Summarize likely causes, evidence, remediation, and validation steps using `references/report-template.md`.

## 1. Intake

Collect:
- Target view or feature code.
- Symptoms and exact reproduction steps.
- Data flow: `@State`, `@Binding`, environment dependencies, and observable models.
- Whether the issue shows up on device or simulator, and whether it was observed in Debug or Release.

Ask the user to classify the issue if possible:
- CPU spike or battery drain
- Janky scrolling or dropped frames
- High memory or image pressure
- Hangs or unresponsive interactions
- Excessive or unexpectedly broad view updates

For the full profiling intake checklist, read `references/profiling-intake.md`.

## 2. Code-First Review

Focus on:
- Invalidation storms from broad observation or environment reads.
- Unstable identity in lists and `ForEach`.
- Heavy derived work in `body` or view builders.
- Layout thrash from complex hierarchies, `GeometryReader`, or preference chains.
- Large image decode or resize work on the main thread.
- Animation or transition work applied too broadly.

Use `references/code-smells.md` for the detailed smell catalog and fix guidance.

The rest: https://github.com/Dimillian/Skills/blob/HEAD/swiftui-performance-audit/SKILL.md