iOS Developer Interview Questions India 2026

Tip: Structs are value types (copied on assignment), classes are reference types (shared pointer). Structs: no inheritance, thread-safer. Classes: support inheritance, deinit, identity comparison. Prefer structs for data models.

Tip: ARC automatically inserts retain and release calls at compile time — no garbage collector at runtime. Objects are deallocated when their reference count hits 0. ARC is deterministic. The main pitfall is retain cycles.

Tip: Strong: increments retain count (default). Weak: does not retain, becomes nil when deallocated — use for delegates to break cycles. Unowned: like weak but not optional — use when the referenced object always outlives the reference.

Tip: Delegate: a protocol that an object implements to receive callbacks from another object. Classic example: UITableViewDelegate — the table view calls methods on its delegate when a cell is tapped. Hold a weak reference to the delegate to avoid retain cycles.

Tip: UIKit: imperative, 14 years of history, any iOS version. SwiftUI: declarative, state-driven, requires iOS 13+, faster to iterate but less mature. Mixed codebase is common via `UIHostingController` and `UIViewRepresentable`.

Tip: Core Data is Apple's ORM over SQLite (or in-memory). Use for: complex object graphs, undo/redo, CloudKit sync. Overkill for: simple key-value preferences (use UserDefaults), small flat datasets. Consider Realm for simpler use cases.

Tip: URLSession is the native HTTP client. Old pattern: completion handlers (callback hell). Modern: `async/await` with `URLSession.data(for:)` (iOS 15+). Always decode JSON with `Codable`, not manual parsing.

Tip: Name a specific challenge: memory management issue, background fetch timing, complex animation, offline-first sync, or App Store review rejection. Describe the root cause, your fix, and the outcome.

Tip: Read the rejection reason carefully — common ones: missing privacy usage descriptions in Info.plist, incomplete metadata, crash on reviewer's device, in-app purchase not tested, or guideline violation. Reply in Resolution Center with specifics.

Tip: `viewDidLoad` is called once after the view hierarchy is loaded — good for one-time setup: layout constraints, delegate assignment, data loading. Do NOT put layout-dependent code here needing accurate frame sizes — use `viewDidLayoutSubviews`.

Tip: Read the deprecation notice in release notes. Check the replacement API. Use `#available` for version-gated migration. Set a timeline to remove the old code path once minSdkVersion advances. Test on both OS versions.

Tip: Show specifics: WWDC sessions, Swift Evolution proposals, Apple developer documentation, Hacking with Swift. Mention one recent feature you found interesting (e.g. Swift Concurrency, Swift Data). Generic "I watch WWDC" is not enough.