DevPrep: Coding Interview

Prepare for your iOS developer interview with a plan — 5–10 minutes a day. Hundreds of questions across 22 topics and 800+ interactive challenges — the library grows regularly: Swift, SwiftUI, Swift Concurrency (async/await, actors), Combine, memory & ARC, multithreading & GCD, UIKit, Auto Layout, architecture (MVVM, VIPER, Clean), Objective-C, algorithms & data structures, networking, testing and soft skills. WHAT'S INSIDE • Practice: 800+ challenges in 8 formats — what does it print, find the bug, assemble the code, pick the fix, fill in the blank, will it crash?, estimate the complexity, select all that apply — with hints, explanations, Easy / Medium / Hard difficulty and a personal feed that targets your weakest topics • Company prep: interview stages at 24 tech companies based on public candidate reports, what candidates were asked, and a day-by-day plan up to your interview date • Timed mock interviews, a weekly challenge, tracks and an activity calendar • Mobile system design: 20 cases with step-by-step walkthroughs and self-checks • Behavioral interviews: 46 questions, your own STAR stories and timed drills • Today: what to review, what to learn next, a daily puzzle and your weak spots • A prep roadmap for Junior, Middle and Senior — stages with must-know checklists • Tasks from real interviews and “what does this code print” puzzles with full solutions • Spaced-repetition trainer: missed cards come back in the same session • Apple-docs-style answers with Swift 6 code and syntax highlighting • A level filter across the whole library — study exactly what you need • Progress by topic, a daily streak and goal • Daily reminders and progress sync via iCloud • Light and dark themes, Russian and English — switch on the fly • Works fully offline — all content is saved on your device • Optimized for iPhone Duo and iPad We continuously update and expand the library of questions and tasks — new content arrives without an app update. Basic topics are free. Full access to all questions, tasks and materials unlocks with a subscription. SUBSCRIPTION Payment is charged to your Apple ID at confirmation of purchase. It auto-renews unless auto-renew is turned off at least 24 hours before the end of the current period. Manage your subscription in your Apple ID settings. Terms of use and the privacy policy are available in the app.