Instagram Reels Clone

An example iOS application that replicates the Instagram Reels experience using SwiftUI.

Why This Project Exists

• Demonstrate how to build a short-form video feed experience on iOS using a clear, learnable architecture.
• Provide a practical reference for combining SwiftUI, AVKit, and Combine in one app.
• Explore interaction-heavy UI behaviors (scroll-driven feed, playback controls, comments, like state) with maintainable code.
• Serve as a foundation for extending into production-like features such as API integration, caching, and analytics.

Trade-off Analysis

• SwiftUI over UIKit: Faster iteration and cleaner declarative UI, but less granular control for some complex video interactions compared to UIKit.
• MVVM simplicity vs strict Clean layering: Easier onboarding and lower boilerplate, but some domain/data concerns may need further separation as the app grows.
• In-memory mock data vs backend persistence: Speeds up development and demos, but does not represent real network latency, offline sync, or data consistency challenges.
• One VideoPlayerViewModel per reel: Better playback/state isolation, but higher memory footprint when feed size scales.
• Local state management (@Published) vs global store: Straightforward for current scope, but coordination across many features can become harder without centralized state patterns.

Metrics (Measurement Results)

Current project status:

• Automated test coverage: Not yet established (no committed XCTest/XCUITest suite in this repository snapshot).
• Performance benchmark suite: Not yet established (no committed Instruments trace baselines).
• Build and run target: App is configured for iOS simulator/device execution in Xcode 26.2.

Recommended baseline metrics to add and track:

• Cold launch time: Measure with Instruments (Time Profiler) on a fixed simulator/device profile.
• Reel first-frame time: Time from reel visibility to first rendered video frame.
• Scroll smoothness: FPS and dropped frame rate during rapid reel feed navigation.
• Memory usage: Peak and steady-state memory while browsing N reels continuously.
• Playback reliability: Video start success rate and rebuffer/failed-playback frequency.

Features

• Reels feed: Vertically scrollable list of short videos.
• Video playback: Play/pause, mute/unmute and time slider control for each reel.
• Likes & comments: Manage like state for reels and comments.
• Multi-tab navigation: Home, Reels, Search, Profile and Share tabs.

Technologies & Techniques Used

• Language: Swift
• UI Framework: SwiftUI
  • @main app entry (InstagramReelsApp)
  • Multi-tab interface (InstaContentView, InstaHomeView, Reels / Search / Profile / Share views)
• Architecture:
  • MVVM style separation
  • State management with ObservableObject and @Published (InstaReelsViewModel, VideoPlayerViewModel)
• Reactive Programming:
  • Combine (AnyCancellable, key-path publishers for observing AVPlayerItem status)
• Media Playback:
  • AVKit / AVFoundation (AVPlayer, AVPlayerItem, CMTime)
  • Periodic time observer to track current time and total duration
• UI Helpers:
  • @MainActor to ensure UI updates on the main thread
  • UIScreen.main.bounds for layout based on screen size
• Data Model:
  • Strongly typed models: Profile, Reel, Comment, Audio
  • Mock data providing sample reels and comments

Project Structure (Overview)

• App/: Application entry (InstagramReelsApp.swift)
• ContentView/Tabs/Reels:
  • Models/ → Reel, Profile, Comment, Audio models
  • State/ → InstaAppState (Reels-related state)
  • ViewModel/ → InstaReelsViewModel, VideoPlayerViewModel
  • Views/ → InstaReelsView, VideoPlayerView, VideoTimeSlider, PlaybackControlsView, ReelCommentsSheet
• ContentView/Tabs/*: SwiftUI views for Home, Search, Profile, Share tabs
• Extensions/: Utility extensions (CGFloat+Extension.swift)
• Resources/Assets.xcassets: Colors, app icon, and profile placeholder images

Development Environment

• Xcode: 26.2
• iOS Target: iOS 17.0+

How to Run

• 1. Open InstagramReels.xcodeproj in Xcode.
• 2. Select an iOS 16+ simulator or a physical device as the run destination.
• 3. Press Run (⌘ + R) to build and launch the app.