# DevPrep vs System Design Refresher

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.

Both are free to download. DevPrep sells 5 one-off in-app purchases. System Design Refresher asks for nothing beyond the download.

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.

## The numbers

| Metric | DevPrep | System Design Refresher |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 days** | Monthly |
| Size | 149 MB | 18 MB |
| Requires iOS | **15.1** | 26.2 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Thieu Khue](https://appshunter.io/developer/1554439862) | [Saurabh Sharma](https://appshunter.io/developer/1883599017) |

## What reviewers say

### DevPrep

[App page](https://appshunter.io/ios/app/devprep-ai-interview-coach/id6755906092)

**Features:** macOS Compatibility

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Backend Scale pack | $9.99 | one-time |
| Data Structure & Algorithms pack | $9.99 | one-time |
| System Design pack | $9.99 | one-time |
| Frontend Engineering pack | $9.99 | one-time |
| Unlock all Pro Packs | $29.99 | one-time |


### System Design Refresher

[App page](https://appshunter.io/ios/app/system-design-refresher/id6760277935)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked 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.

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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.*