# System Design interview prep vs Performance Engineer Trainer

The clearest difference is in-app purchases: Performance Engineer Trainer at none against System Design interview prep's 5. Performance Engineer Trainer also leads on ads (none vs shown) and update cadence (every 4 days vs monthly). On price, device support and iOS requirement there is nothing between them.

Both are free to download. System Design interview prep sells 5 in-app purchases, starting at $3.99 per 7 days. Performance Engineer Trainer asks for nothing beyond the download.

System Design interview prep ships an update monthly, Performance Engineer Trainer every 4 days. The most recent releases landed on September 26, 2026 and September 29, 2026 respectively.

## The numbers

| Metric | System Design interview prep | Performance Engineer Trainer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.0 (2 ratings)](https://appshunter.io/ios/app/system-design-interview-prep/id6756310915/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Monthly | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 89 MB | 4 MB |
| Requires iOS | 17.6 | **16.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 17+ |
| Developer | [Abdelhak El Moussaoui](https://appshunter.io/developer/1827690433) | [Kirill Kalistratov](https://appshunter.io/developer/1888794382) |

## What reviewers say

### System Design interview prep

[App page](https://appshunter.io/ios/app/system-design-interview-prep/id6756310915)

This app simulates system design interviews with an AI interrogator and interactive scenarios. Practice real-world architecture problems, receive instant feedback, and track your progress to ace your next tech interview.

**Highlights:** Interactive War Room for architecture scenarios, AI Interrogator challenges design decisions, Realistic system design interview questions, Daily practice drills for skill sharpening, Detailed performance analytics, Instant feedback and best practice learning

**Features:** macOS Compatibility

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlimited access | $3.99 | per 7 days |
| Unlimited access | $4.99 | per 7 days |
| Unlimited access | $6.99 | per month |
| Unlimited access | $12.99 | per month |
| Unlimited access | $99.99 | per year |


### Performance Engineer Trainer

[App page](https://appshunter.io/ios/app/performance-engineer-trainer/id6761308281)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is System Design interview prep free?

System Design interview prep is free to download, with in-app purchases available.

### Is Performance Engineer Trainer free?

Performance Engineer Trainer is free to download, with no in-app purchases.

### Do System Design interview prep or Performance Engineer Trainer have ads?

System Design interview prep shows ads; Performance Engineer Trainer does not.

### Which is updated more often, System Design interview prep or Performance Engineer Trainer?

System Design interview prep ships an update monthly, and Performance Engineer Trainer every 4 days. Most recently, System Design interview prep was updated on September 26, 2026 and Performance Engineer Trainer on September 29, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*