Comparison

DevPrep vs Delta IS Mobile

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

DevPrep

Features
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Prepare for your iOS developer interview with a plan — 5–10 minutes a day. Hundreds of questions across 20+ topics and 1,000+ 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: 1,000+ challenges in 9 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, is this API real? — with hints, explanations, Easy / Medium / Hard difficulty and a personal feed that targets your weakest topics • AI-assisted development: review AI-generated code, spot made-up and deprecated APIs, prompts and context, theory and ready-made project rule templates — ship code with AI faster and with confidence • iOS and AI dev news: today's highlights in short, full articles right in the app and one-tap translation • Daily challenge and Streak widgets, Siri and Shortcuts, find articles right from iPhone search • On-device AI on iPhones with Apple Intelligence: explain answers in your own words and get hints • Company prep: interview stages at 24 tech companies based on public candidate reports, what candidates were asked, a day-by-day plan up to your interview date — and you can share your own questions • 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 and the daily challenge 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.

About

Delta IS Mobile

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Приложение для сотрудников международной школы робототехники "Лига Роботов"

Screenshots

DevPrep4 screens
Delta IS Mobile4 screens

Verdict

The call

The clearest difference is in-app purchases: Delta IS Mobile at none against DevPrep's 4. Delta IS Mobile also leads on iOS requirement (13.0 vs 17.0). DevPrep's advantage is device support. On price there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. DevPrep sells 4 in-app purchases, starting at $2.99 per 6 months. Delta IS Mobile asks for nothing beyond the download.

Scorecard3 real differences · 3 level
DevPrep versus Delta IS Mobile: the parameters behind the verdict, then further details
ParameterDevPrepDelta IS Mobile
PriceFreeFree
Update frequencyEvery 2 days—
AdsYes—
In-app purchasesYesNo — better
DevicesiPhone, iPad, Mac — better—
Requires iOS17.013.0 — better
Further details — not scored
Size49 MB23 MB
Age rating4+4+
DeveloperAliaksei YelinOleg Marchenko

In-app purchases

4 purchases

DevPrep

Subscriptions3
  • Get full access3 Days trial$2.996 Months
  • Full Access · Monthly3 Days trial$4.991 Month
  • Full Access · Year3 Days trial$29.991 Year
One-time1
  • Full Access · Lifetime$39.99
None

Delta IS Mobile

No in-app purchases

Questions

Is DevPrep free?
DevPrep is free to download, with in-app purchases available.
Is Delta IS Mobile free?
Delta IS Mobile is free to download, with no in-app purchases.

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