# Proto.io vs System Designer

The clearest difference is rating: System Designer at 4.4 against Proto.io's 3.7. System Designer also leads on review sentiment (78% vs 42%) and update cadence (monthly vs every 4 months). Proto.io's advantage is iOS requirement (10.0 vs 15.6). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

System Designer holds the better App Store score, 4.4 against 3.7. Both are backed by a comparable volume of ratings — 6 and 17 respectively. Written reviews point the same way: 42% of Proto.io's written reviews are positive against 78% of System Designer's.

Proto.io ships an update every 4 months, System Designer monthly. The most recent releases landed on October 20, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Proto.io | System Designer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.7 (6 ratings)](https://appshunter.io/ios/app/protoio/id854504039/reviews) | **[4.4 (17 ratings)](https://appshunter.io/ios/app/system-designer/id1132983280/reviews)** |
| Number of ratings | 6 | **17** |
| Positive reviews | 41.9% of reviews | **77.8% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Monthly** |
| Monetization | Free | Free |
| Size | 34 MB | 7 MB |
| Requires iOS | **10.0** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Proto.io](https://appshunter.io/developer/854504042) | [Erwan Carriou](https://appshunter.io/developer/1102494853) |

## What reviewers say

### Proto.io

[App page](https://appshunter.io/ios/app/protoio/id854504039)

This application allows users to preview and interact with their Proto.io projects on any device. It supports native touch gestures for a realistic prototyping experience and offers offline viewing of cached projects. Users can also record and share their prototype interactions.

**Highlights:** Preview shared Proto.io projects, Access all projects from your account, Full-screen prototype viewing, Interact with native touch gestures, Preview on any device/screen size, Offline viewing of cached projects, Record and share prototype interactions

**Features:** macOS Compatibility

**In-app purchases:** none

**What reviewers like**

- 👍 Easy to use for prototyping
- 🚀 Powerful features for prototyping
- 💡 Makes prototyping simple and quick
- ✨ Responsive and easy to use prototype
- 🔄 Live updates from computer to phone

**What reviewers complain about**

- 🐛 Can't login
- 🐛 Difficult to delete account
- 🐛 Share link issues
- 🐛 Login issues
- 🐛 Bad app

**Reported bugs**

- Can't login
- Difficult to delete account
- Share link issues
- Login issues
- Cannot sign up or sign in

**Requested features**

- Update UI elements for iOS 13
- Caching projects
- Optimise application for iPhone 6 screen
- Easily switch between accounts like Tweetbot


### System Designer

[App page](https://appshunter.io/ios/app/system-designer/id1132983280)

Design complex systems using a low-code platform that leverages UML standards. Generate code skeletons and manage components graphically. Run and test your system with dynamic type checking.

**Highlights:** UML-based system modeling, Code skeleton generation, Graphical component creation, MSON format for model definition, Dynamic type checking, Cross-device synchronization via GitHub

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Proto.io free?

Proto.io is free to download, with no in-app purchases.

### Is System Designer free?

System Designer is free to download, with no in-app purchases.

### Which has better reviews, Proto.io or System Designer?

System Designer is rated higher. Proto.io averages 3.7 out of 5 from 6 ratings, while System Designer averages 4.4 from 17 ratings.

### Do Proto.io or System Designer have ads?

Neither Proto.io nor System Designer shows ads.

### Which is updated more often, Proto.io or System Designer?

Proto.io ships an update every 4 months, and System Designer monthly. Most recently, Proto.io was updated on October 20, 2026 and System Designer on October 6, 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.*