#mobile

7 mobile interview questions, asked at OpenAI, Apple, Google and 1 more company. Last asked Sep 2026.

Design an offline-first client that syncs edits across devicesSystem designDesign the client side of an app in which users edit data over an unreliable network. Every edit is saved to local storage on the device as it is made, and the user keeps working…
Last asked Sep 2026
Design cloud photo storage with sync across devicesSystem designDesign a photo library in the cloud that keeps every one of a user's devices in sync: upload new photos from a phone, see them on the other devices, and propagate edits and…
Last asked Aug 2026
Build a chat screen in an existing iOS codebaseCodingYou get an existing mobile app codebase and build a chat interface inside it: a list of messages and a field to send new ones, wired into the app's existing code. The round is…
Last asked Jul 2026
Design wallpaper sync across a user's devicesSystem designWhen a user sets a wallpaper on one device, it should show up on their other devices. Design that sync: storing the image and its settings, notifying the other devices, devices…
Last asked Jun 2026
Design the API layer of an Android app with MVVMSystem designDesign how an Android app talks to its backend API using the MVVM pattern: the layers from the network client up through repositories and view models to the screen, and what each…
Last asked May 2026
Design per-user model usage quotas for a mobile appSystem designDesign how a mobile app enforces per-user quotas on model usage: how usage is counted, where the limit is enforced, what the app shows the user as they approach and reach it, and…
Last asked May 2026
Design a fitness tracking appSystem designDesign a fitness tracking app: users record workouts such as runs and rides from their phone, see their history, and view the route of each workout on a map. Cover uploading…
Last asked Mar 2026