Comparison

DevPrep vs System Design Refresher

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

Head to head
About

DevPrep

Features
Read full description

You have the coding skills, but can you explain them clearly under pressure? DevPrep is the Offline-First AI Interview Coach designed specifically for Software Engineers. Stop practicing in your head. Start speaking. DevPrep simulates the pressure of a real interview, records your answer, and uses an advanced on-device AI engine to grade your response against ideal technical answers. WHY DEVPREP? • AI GRADING ENGINE: Our local vector-based AI analyzes your speech for technical accuracy, logic, and clarity. Get a score (0-100) instantly. • PRIVACY & FAST: All grading happens securely on your device. Your voice recording is processed locally. • ZERO FLUFF: 250+ curated questions from the current tech industry standards. 5 SPECIALIZED TRACKS: - SOFT SKILLS & LEADERSHIP - DATA STRUCTURES & ALGORITHMS (pro) - SYSTEM DESIGN ARCHITECT (pro) - MODERN FRONTEND ENGINEERING (pro) - BACKEND & DISTRIBUTED SYSTEMS (pro) FEATURES: - Realistic "Interviewer" Audio to simulate pressure. - "Silent Mode" for practicing on the go (multi-choice questions). - Local progress feature to track your mastery. - Offline-First architecture (Privacy focused).

About

System Design Refresher

Features
Read full description

System Design Refresher is a free study companion for software engineers preparing for system design interviews. WHAT'S INSIDE • 30+ system design articles covering distributed systems, databases, caching, and more • Engineering blogs from top tech companies (Google, Meta, Stripe, Airbnb, and more) aggregated in one place • AI-powered flashcards with spaced repetition • Ask AI to summarize or explain any article in plain language • Favorites, reading progress tracking, and custom RSS feeds FEATURES • Works offline — articles download for reading without internet • Dark mode, font customization, and text size controls • Face ID / Touch ID lock for privacy • Sign in with Google or Apple, or use as a guest with no account required

Screenshots

DevPrep4 screens
System Design Refresher4 screens

Verdict

The call

The clearest difference is in-app purchases: System Design Refresher at none against DevPrep's 5. DevPrep's advantage is update cadence (every 2 days vs monthly) and iOS requirement (15.1 vs 26.2). On price, ads and device support 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 5 one-off in-app purchases. System Design Refresher asks for nothing beyond the download.

UpkeepUpdate frequency

DevPrep ships an update every 2 days, System Design Refresher monthly. The most recent releases landed on September 24, 2026 and September 12, 2026 respectively.

Scorecard3 real differences · 3 level
DevPrep versus System Design Refresher: the parameters behind the verdict, then further details
ParameterDevPrepSystem Design Refresher
PriceFreeFree
Update frequencyEvery 2 days — betterMonthly
AdsNoNo
In-app purchasesYesNo — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.1 — better26.2
Further details — not scored
Size149 MB18 MB
Age rating4+4+
DeveloperThieu KhueSaurabh Sharma

In-app purchases

5 purchases

DevPrep

One-time5
  • Backend Scale pack$9.99
  • Data Structure & Algorithms pack$9.99
  • System Design pack$9.99
Show 2 more
  • Frontend Engineering pack$9.99
  • Unlock all Pro Packs$29.99
None

System Design Refresher

No in-app purchases

Questions

Is DevPrep free?
DevPrep is free to download, with in-app purchases available.
Is System Design Refresher free?
System Design Refresher is free to download, with no in-app purchases.
Do DevPrep or System Design Refresher have ads?
Neither DevPrep nor System Design Refresher shows ads.
Which is updated more often, DevPrep or System Design Refresher?
DevPrep ships an update every 2 days, and System Design Refresher monthly. Most recently, DevPrep was updated on September 24, 2026 and System Design Refresher on September 12, 2026.

Other comparisons