Proto.io vs Principle Mirror
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- 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
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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
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 Proto.io's 3.7. On price, review sentiment, ratings volume and update cadence 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 3.7. Both are backed by a comparable volume of ratings — 6 and 14 respectively. Written reviews point the same way: 42% of Proto.io's written reviews are positive against 45% of Principle Mirror's.
Proto.io ships an update every 4 months, Principle Mirror every 2 months. The most recent releases landed on October 23, 2026 and October 28, 2026 respectively.
| Parameter | Proto.io | Principle Mirror |
|---|---|---|
| Price | Free | Free |
| Rating | 3.7 (6 ratings) | 4.2 (14 ratings) — better |
| Positive reviews | 41.9% of reviews | 45.2% of reviews — better |
| Number of ratings | 6 | 14 — better |
| Update frequency | Every 4 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 | 10.0 — better | 11.0 |
| Further details — not scored | ||
| Size | 34 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Proto.io | Daniel Hooper |
Customer experience
Proto.io
Principle Mirror
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
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- 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
Principle Mirror
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Proto.io
No in-app purchases
Principle Mirror
No in-app purchases
Questions
Is Proto.io free?
Is Principle Mirror free?
Which has better reviews, Proto.io or Principle Mirror?
Do Proto.io or Principle Mirror have ads?
Which is updated more often, Proto.io or Principle Mirror?
Other comparisons
