System Design
Mobile System Design Interviews
A practical mobile system design course - a repeatable interview framework, a mobile toolbox, and eight full app case studies (social feed, chat, video streaming, ride sharing, cloud storage and more) worked end to end.
Mobile System Design Interviews
Mobile system design interviews are their own discipline. They are less about planet-scale backends and more about the realities of the device and the network: offline-first behaviour, sync and conflict resolution, caching and pagination, battery and bandwidth, push delivery, local storage, and a responsive UI under flaky connectivity.
This course trains that skill directly. You start with a repeatable interview framework and a mobile toolbox of the patterns that come up again and again (API design for mobile, caching and pagination, offline support, real-time updates, and client architecture). Then you work through eight complete app case studies, each taken end to end:
- Social Feed App, Chat Application, Video Streaming App, Hotel Booking App
- Realtime Financial App, Cloud Storage App, Pagination Library, Ride Sharing App
Every case study follows the same arc - problem and discovery, API design, architecture, focused deep dives (feed loading and caching, offline and interactions, and more), and a summary with variations and interview tips - so the framework becomes second nature. The course closes with cheat sheets you can review the day before an interview.
The first two modules are free to preview. The full course is a one-time purchase with lifetime access.
What you will learn
- A repeatable framework for any mobile system design interview question
- The mobile toolbox: API design for mobile, caching, pagination, and client architecture
- Offline-first design: local storage, sync, and conflict resolution
- Real-time updates, push delivery, and handling flaky connectivity gracefully
- Performance on-device: battery, bandwidth, memory, and a responsive UI
- How to scope a mobile product, define requirements, and design clean client APIs
- Eight full app case studies worked end to end - from social feed to ride sharing
- Cheat sheets and common mistakes to review right before the interview
Prerequisites
- Some mobile development experience (iOS, Android, or cross-platform) helps
Course outline
Module 1: Welcome
Welcome - 1 topics.
Module 2: The Mobile Interview Framework
The Mobile Interview Framework - 7 topics.
- How Mobile System Design Interviews Actually Work 4 min read
- The 5-Step Framework - Your Interview Playbook 6 min read
- Step 1: Understand the Problem - The Detective Phase 10 min read Pro lesson
- Step 2: API Design - The Contract Phase 5 min read Pro lesson
- Step 3: High-Level Architecture - The Blueprint Phase 6 min read Pro lesson
- Step 4: Deep Dives - The Engineering Phase 8 min read Pro lesson
- Step 5: Wrap-Up - The Presentation Phase 5 min read Pro lesson
Module 3: The Mobile Toolbox
The Mobile Toolbox - 12 topics.
- Architecture Patterns for Mobile Apps 15 min read
- Data Storage on Mobile - Choosing the Right Home for Your Data 15 min read
- Networking Fundamentals - How Your App Talks to the World 17 min read
- Authentication & Security - Keeping the Front Door Locked 17 min read Pro lesson
- Pagination - Loading Data One Page at a Time 13 min read Pro lesson
- Caching - The Art of Remembering So You Don't Have to Ask Again 17 min read Pro lesson
- Push Notifications - Tapping Users on the Shoulder 15 min read Pro lesson
- Offline Support - Making Your App Work Without Internet 17 min read Pro lesson
- Image Loading & CDN - Delivering Visual Content Fast 14 min read Pro lesson
- Performance Optimization - Making Your App Feel Instant 16 min read Pro lesson
- Accessibility & Localization - Building for Everyone 15 min read Pro lesson
- CI/CD & App Releases - Shipping With Confidence 17 min read Pro lesson
Module 4: Case Study - Social Feed App
Case Study - Social Feed App - 6 topics.
- Social Feed App - Problem & Discovery 5 min read
- Social Feed App - API Design 8 min read
- Social Feed App - High-Level Architecture 12 min read
- Social Feed App - Deep Dive: Feed Loading & Caching 13 min read
- Social Feed App - Deep Dive: Offline Support & User Interactions 9 min read
- Social Feed App - Summary & Variations 9 min read
Module 5: Case Study - Chat Application
Case Study - Chat Application - 6 topics.
- Chat Application - Problem & Discovery 5 min read
- Chat Application - API Design 7 min read
- Chat Application - High-Level Architecture 11 min read Pro lesson
- Chat Application - Deep Dive: Real-Time Messaging & Message Ordering 11 min read Pro lesson
- Chat Application - Deep Dive: Offline Support & Data Storage 9 min read
- Chat Application - Summary & Variations 8 min read Pro lesson
Module 6: Case Study - Video Streaming App
Case Study - Video Streaming App - 6 topics.
- Video Streaming App - Problem & Discovery 4 min read Pro lesson
- Video Streaming App - API Design 6 min read Pro lesson
- Video Streaming App - High-Level Architecture 9 min read Pro lesson
- Video Streaming App - Deep Dive: Video Playback & Streaming 11 min read Pro lesson
- Video Streaming App - Deep Dive: Feed Optimization & Prefetching 8 min read Pro lesson
- Video Streaming App - Summary & Variations 6 min read Pro lesson
Module 7: Case Study - Hotel Booking App
Case Study - Hotel Booking App - 6 topics.
- Hotel Booking App - Problem & Discovery 6 min read Pro lesson
- Hotel Booking App - API Design 7 min read Pro lesson
- Hotel Booking App - High-Level Architecture 11 min read Pro lesson
- Hotel Booking App - Deep Dive: Search & Filtering 12 min read Pro lesson
- Hotel Booking App - Deep Dive: Reservation & Payment Flow 8 min read Pro lesson
- Hotel Booking App - Summary & Variations 7 min read Pro lesson
Module 8: Case Study - Realtime Financial App
Case Study - Realtime Financial App - 6 topics.
- Real-Time Financial App - Problem & Discovery 6 min read Pro lesson
- Real-Time Financial App - API Design 5 min read Pro lesson
- Real-Time Financial App - High-Level Architecture 9 min read Pro lesson
- Real-Time Financial App - Deep Dive: Live Data & Charts 11 min read Pro lesson
- Real-Time Financial App - Deep Dive: Trading & Data Reliability 7 min read Pro lesson
- Real-Time Financial App - Summary & Variations 6 min read Pro lesson
Module 9: Case Study - Cloud Storage App
Case Study - Cloud Storage App - 6 topics.
- Cloud Storage App - Problem & Discovery 6 min read Pro lesson
- Cloud Storage App - API Design 5 min read Pro lesson
- Cloud Storage App - High-Level Architecture 9 min read Pro lesson
- Cloud Storage App - Deep Dive: File Upload & Sync 12 min read Pro lesson
- Cloud Storage App - Deep Dive: Versioning & Security 7 min read Pro lesson
- Cloud Storage App - Summary & Variations 7 min read Pro lesson
Module 10: Case Study - Pagination Library
Case Study - Pagination Library - 6 topics.
- Pagination Library - Problem & Discovery 5 min read Pro lesson
- Pagination Library - API Design 6 min read Pro lesson
- Pagination Library - Architecture 9 min read Pro lesson
- Pagination Library - Deep Dive: Caching & State Management 11 min read Pro lesson
- Pagination Library - Deep Dive: Flexibility & Error Handling 7 min read Pro lesson
- Pagination Library - Summary & Variations 7 min read Pro lesson
Module 11: Case Study - Ride Sharing App
Case Study - Ride Sharing App - 6 topics.
- Ride-Sharing App - Problem & Discovery 6 min read Pro lesson
- Ride-Sharing App - API Design 7 min read Pro lesson
- Ride-Sharing App - High-Level Architecture 14 min read Pro lesson
- Ride-Sharing App - Deep Dive: Maps & Real-Time Location 13 min read Pro lesson
- Ride-Sharing App - Deep Dive: Ride Flow & Payments 11 min read Pro lesson
- Ride-Sharing App - Summary & Variations 9 min read Pro lesson
Module 12: Cheat Sheets
Cheat Sheets - 3 topics.
- Interview Day Cheat Sheet 4 min read Pro lesson
- Common Patterns & When to Use Them 7 min read Pro lesson
- Common Mistakes & Red Flags in Mobile System Design Interviews 9 min read Pro lesson