What is mobile-system-design?

This repository is a study guide for mobile system design interviews, aimed at people preparing for iOS and Android engineering roles. It is a copy of an existing popular guide, and it lays out a framework for how to approach these interviews rather than a checklist of correct answers. The core idea is that interviewers care mostly about how a candidate thinks and communicates, not about producing a perfect finished design within a short time slot. The guide walks through a typical 45 to 60 minute interview structure step by step: brief introductions, defining the scope of the task, gathering requirements, discussing a high level design, and then diving into more detail before wrapping up with questions for the interviewer. It explains how to figure out whether the interviewer wants a client only design, a client plus API design, or a full client, API, and backend design, and suggests being honest about the limits of your backend knowledge if that is not your area. A large part of the guide focuses on gathering requirements using a worked example of designing a Twitter style feed. It shows how to sort requirements into functional features users need, non functional qualities like offline support and real time notifications, and things that are explicitly out of scope for the interview. It also lists many clarifying questions a candidate should consider asking, covering topics like target markets, expected user counts, team size, target devices, performance expectations, data consistency needs, update frequency, and the types of media involved. Later sections describe a sample high level architecture for the feed example, breaking it into server side pieces like the backend, a push notification provider, and a content delivery network, along with client side pieces such as an API service layer, a local persistence layer, a repository that mediates between the two, a dependency injection setup, an image loading component, and a navigation coordinator. Throughout, the guide repeats the idea that showing clear reasoning, stated assumptions, and awareness of trade offs matters more than memorizing a single correct architecture. This project is aimed at mobile developers preparing for job interviews, as well as engineers curious about how mobile app architecture decisions are typically explained and justified. The full README is longer than what was shown.