Mobile System Design Interview
For mobile engineers preparing for a mobile system design round, where you design the app on the phone rather than the servers behind it. You will learn a repeatable 45-minute framework and the mobile building blocks behind it, then apply them to seven worked case studies, from a news feed to a video player — 23 lessons in 11 sections, about 19 hours.
Course Content
Learn how the mobile round differs from backend system design, what interviewers score, how much server detail to give, and the failures that sink most answers. 2 lessons, about 40 minutes.
Learn a seven-step, 45-minute framework — clarifying questions, the API contract, client architecture, data flow, and a closing sweep of constraints — that you can reuse on any prompt. 2 lessons, about 70 minutes.
Build the vocabulary every case study relies on: the mobile constraints, networking, persistence, caching, pagination, offline-first sync, background work, media, security, and safe rollout. 3 lessons, about 180 minutes.
Design an infinitely scrolling social feed that stays smooth on low-end devices, never jumps as images load, and reads offline from a local database. 2 lessons, about 120 minutes.
Design a chat client that never loses or duplicates a message, using a socket-to-push handoff, a persisted outbox, and server-assigned ordering. 2 lessons, about 120 minutes.
Design a trading app that coalesces hundreds of price updates a second, renders charts efficiently, flags stale prices, and places orders safely over an unreliable network. 2 lessons, about 120 minutes.
Design a reusable pagination library for other engineers, with a small public API, deduplicated loads, caching that composes with the app's database, and testability. 2 lessons, about 100 minutes.
Design a hotel booking app whose multi-step flow survives process death and whose payment step can never charge the user twice. 2 lessons, about 100 minutes.
Design a cloud file storage client with an offline folder tree, resumable background transfers, a dependency-aware sync engine, and conflict resolution that never loses work. 2 lessons, about 120 minutes.
Design a video streaming client covering adaptive bitrate, buffering and fast start, a playback session that outlives the screen, and offline downloads. 2 lessons, about 130 minutes.
Revise the whole course from a few pages: the framework, decision tables, the constraint checklist, the patterns that recur across case studies, and how to keep practising. 2 lessons, about 50 minutes.