Comparison

Proto.io vs System Designer

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

Head to head
About

Proto.io

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
Read full description

Proto.io App brings your Proto.io projects to life! It allows you to use all the native gestures to interact with elements and makes full use of your screen estate. **Key features include:** - Preview projects shared with you - Login and access all your projects in your Proto.io account. - Preview your projects in full screen without any obstructions. - Ability to interact with your projects using all supported touch gestures: Pinch, swipe, tap, tap & hold and more. - Preview any prototype on any device/screen size regardless of the device /screen size it was designed for. - When previewing a project it is saved in your device cache so that you can view it again without an internet connection - Record and share your interactions with a prototype

About

System Designer

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
Read full description

System Designer is a low-code development platform for creating systems. No matter the frameworks you use and the code you write, the most important is the model that you define to create your system. System Designer helps you to design this model and to generate the classes and components to build your system. DESIGN YOUR SYSTEM WITH EASE If you look at the different JavaScript frameworks on the market, you will notice that they all have their own way to define a model, generally only with code. System Designer uses UML, a standard, to define your model. So you probably already know how to design in System Designer even if you have never run it. The definition of the model is stored on a JSON format called MSON. With MSON you can define types, classes, one to one / one to many relationships and multi inheritance between classes. CODE THE BEHAVIOR OF YOUR SYSTEM Once you have created your model, System Designer generates the skeletons of all your methods. You only have then to add your code to implement them. System Designer provides you helpers to manage your components. You can easily navigate threw your components to create your application. CREATE COMPONENTS GRAPHICALLY There is no need to code to instantiate a component. Create a component in System Designer is like creating a document in a NoSQL Database. In fact, System Designer acts as an ODM (Object-Document Mapper) to manage your components as NoSQL Documents. RUN YOUR SYSTEM You can run your system directly from System Designer. Because you have defined a model for your application, a Dynamic Type Check is done on every action of your system. All warnings are send and shown in System Designer. DESIGN ON THE GO System Designer can be used on macOS, iPad or any browsers. System Designer has a Github module to synchronize your work between all these apps. You can begin your design on your Mac and then continue it on your iPad.

Screenshots

Proto.io4 screens
System Designer3 screens

Verdict

The call

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.

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. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

Proto.io ships an update every 4 months, System Designer monthly. The most recent releases landed on October 14, 2026 and October 6, 2026 respectively.

Scorecard4 real differences · 6 level
Proto.io versus System Designer: the parameters behind the verdict, then further details
ParameterProto.ioSystem Designer
PriceFreeFree
Rating3.7 (6 ratings)4.4 (17 ratings) — better
Positive reviews41.8% of reviews77.8% of reviews — better
Number of ratings617 — better
Update frequencyEvery 4 monthsMonthly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS10.0 — better15.6
Further details — not scored
Size34 MB7 MB
Age rating4+4+
DeveloperProto.ioErwan Carriou

Customer experience

Proto.io

All ratings6 ratings
Positive66.7%
Neutral0.0%
Negative33.3%
Written reviews55 reviews
Positive41.8%
Neutral1.8%
Negative56.4%

System Designer

All ratings17 ratings
Positive88.2%
Neutral0.0%
Negative11.8%
Written reviews9 reviews
Positive77.8%
Neutral0.0%
Negative22.2%

Bugs and requests

Proto.io

Reported bugs

37 issues
  • Can't login
  • Difficult to delete account
  • Share link issues
  • Login issues
  • Cannot sign up or sign in
Show 32 more
  • VR Prototyping is broken
  • App doesn't work at all
  • Blank screen
  • Super buggy on iOS
  • Entire preview offset
  • Projects broken on iPad
  • Videos & transitions won't load on iPad
  • On Device is broken iPhone and iPad
  • Black screen permanently on device
  • Crashes when downloading project
  • Doesn't show prototypes on iOS 10
  • Bug keeps closing the app
  • Crashing on iOS10
  • Crashes constantly
  • Crashes after trying to open a project
  • Crashing after sign in page
  • Not flawless
  • Need to fix some bugs
  • Requires account creation to view
  • Bad update
  • Does not install on iOS 7
  • App does not open, crashes immediately
  • Totally broken, doesn't load on phone
  • Can't get passed loading screen
  • System runs slow
  • Piece of crap app cost me a grade
  • Won't load anything
  • Newest update broke sign-in
  • Very buggy app
  • Crashing or not loading larger elements
  • Gets stuck when loading prototype
  • App has potential but is still buggy

Requested features

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

System Designer

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Proto.io

No in-app purchases

None

System Designer

No in-app purchases

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 14, 2026 and System Designer on October 6, 2026.

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