iosNudge

iOS system design

Design real iOS apps and SDKs, step by step.

Written for interviews Swift that runs in the browser Simple English with examples

Each question walks through requirements, architecture, data model, APIs and deep dives like caching, offline mode and real-time updates.

Design full iOS apps and SDKs, step by step.

8 questions 7h 15m total
  • Design an Image Loading Library

    Build a Kingfisher-style library with a memory and disk cache, shared in-flight requests, downsampling, and safe cancellation in reused cells.

    Hard1h
  • Design an Infinite-Scroll News Feed

    Design a social feed with cursor pagination, prefetching, optimistic likes and an offline cache that opens instantly.

    Medium45 mins
  • Design a Chat App

    Design 1:1 and group chat with a WebSocket, server-side ordering, delivery states, an offline outbox and push notifications.

    Hard1h
  • Design an Offline-First Notes App

    Design a notes app that works fully offline and syncs across devices with a local database, a push/pull sync engine and safe conflict resolution.

    Hard1h
  • Design an Analytics SDK

    Design a tiny, crash-safe analytics SDK that many apps embed, with batching, disk persistence, retries with backoff, and privacy controls.

    Medium45 mins
  • Design a Video Streaming App

    Design a Netflix-style iOS client with HLS playback, resume position across devices, offline downloads and background download sessions.

    Hard1h
  • Design a Ride-Hailing Rider App

    Design an Uber-style rider app with a live driver on the map, a trip state machine that survives app kills, and battery-aware location.

    Hard1h
  • Design the Networking Layer for a Large App

    Design a typed, testable networking layer with endpoints, a middleware chain, single-flight token refresh, safe retries and clear errors.

    Medium45 mins