Justinmind vs System Designer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Justinmind
Create fully functional mobile app prototypes with advanced gestures, transitions, and effects. View and test your designs on mobile devices, even offline, for seamless demos and presentations.
- Create interactive prototypes
- Mobile gestures and transitions
- Offline prototype viewing
- Cloud sharing
- Mobile and tablet adaptation
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Justinmind’s prototyping tool is a one-stop shop for interaction design. Go far beyond a simple hotspot and create fully functional prototypes with mobile gestures, transitions and effects. Design mobile app prototypes that behave like the real thing! All your work created with Justinmind’s prototyping tool can be shared on the cloud. Once your prototypes are in the cloud, they become accessible via the Justinmind app viewer. This means you are free to test and experience your work using your mobile phone! Download your prototypes and have them at hand, working independent of internet access. Prepare for your demos or UX presentations and assure success, even when offline! The Justinmind app viewer adapts itself to your mobile and tablet devices. If you enjoy using Justinmind app, please share a nice review. It really helps!
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.
- UML-based system modeling
- Code skeleton generation
- Graphical component creation
- MSON format for model definition
- Dynamic type checking
- Cross-device synchronization via GitHub
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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.
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Verdict
The clearest difference is rating: System Designer at 4.4 against Justinmind's 3.3. System Designer also leads on review sentiment (78% vs 52%) and update cadence (monthly vs every 5 months). Justinmind's advantage is iOS requirement (12.0 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
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 3.3. Both are backed by a comparable volume of ratings — 15 and 17 respectively. Written reviews point the same way: 52% of Justinmind's written reviews are positive against 78% of System Designer's.
Justinmind ships an update every 5 months, System Designer monthly. The most recent releases landed on September 15, 2026 and September 18, 2026 respectively.
| Parameter | Justinmind | System Designer |
|---|---|---|
| Price | Free | Free |
| Rating | 3.3 (15 ratings) | 4.4 (17 ratings) — better |
| Positive reviews | 52.4% of reviews | 77.8% of reviews — better |
| Number of ratings | 15 | 17 — better |
| Update frequency | Every 5 months | Monthly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 15.6 |
| Further details — not scored | ||
| Size | 8 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Justinmind | Erwan Carriou |
Customer experience
Justinmind
System Designer
In-app purchases
Justinmind
No in-app purchases
System Designer
No in-app purchases









