Justinmind vs Principle Mirror
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!
Principle Mirror
Design interactive user interfaces with this companion app for a popular Mac design tool. Seamlessly open Principle files or mirror your Mac's design work directly to your device.
- Open Principle files
- Mirror Principle for Mac
- Interactive UI design
- Companion app functionality
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Principle Mirror is the companion app to Principle for Mac, a tool for designing interactive interfaces. Principle Mirror can open Principle files from other apps or mirror Principle for Mac when plugged in. “I just wanted to write to you quickly just to say — this. is. amazing. while I was watching the first tutorial I got tears in my eyes! seriously.” Hugo Ahlberg Designer, IDEO "This tool is amazing, very well done." Patrick Wong Designer, Lyft
Screenshots
Verdict
The clearest difference is rating: Principle Mirror at 4.2 against Justinmind's 3.3. Principle Mirror also leads on update cadence (every 2 months vs every 5 months). On price, review sentiment, ratings volume and ads 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.
Principle Mirror holds the better App Store score, 4.2 against 3.3. Both are backed by a comparable volume of ratings — 15 and 14 respectively. Written reviews complicate that: 52% of Justinmind's written reviews are positive against 45% of Principle Mirror's, so the app with the better star average is not the one people write more warmly about.
Justinmind ships an update every 5 months, Principle Mirror every 2 months. The most recent releases landed on June 9, 2026 and September 19, 2026 respectively.
| Parameter | Justinmind | Principle Mirror |
|---|---|---|
| Price | Free | Free |
| Rating | 3.3 (15 ratings) | 4.2 (14 ratings) — better |
| Positive reviews | 52.4% of reviews — better | 45.2% of reviews |
| Number of ratings | 15 — better | 14 |
| Update frequency | Every 5 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 8 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Justinmind | Daniel Hooper |
Customer experience
Justinmind
Principle Mirror
In-app purchases
Justinmind
No in-app purchases
Principle Mirror
No in-app purchases
