# Principle Mirror vs Throughline

The clearest difference is update cadence: Throughline at every 3 days against Principle Mirror's every 2 months. Principle Mirror's advantage is device support (3 vs 1) and iOS requirement (11.0 vs 18.0). On price, 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.

Principle Mirror ships an update every 2 months, Throughline every 3 days. The most recent releases landed on October 24, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Principle Mirror | Throughline |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (14 ratings)](https://appshunter.io/ios/app/principle-mirror/id991911319/reviews)** | — |
| Number of ratings | **14** | — |
| Positive reviews | 45.2% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 days** |
| Monetization | Free | — |
| Size | 1 MB | 5 MB |
| Requires iOS | **11.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Daniel Hooper](https://appshunter.io/developer/419502228) | [Michael Polner](https://appshunter.io/developer/1884811731) |

## What reviewers say

### Principle Mirror

[App page](https://appshunter.io/ios/app/principle-mirror/id991911319)

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.

**Highlights:** Open Principle files, Mirror Principle for Mac, Interactive UI design, Companion app functionality

**Features:** Vision Pro support

**In-app purchases:** none


### Throughline

[App page](https://appshunter.io/ios/app/throughline-ai-voice-notes/id6774304241)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Principle Mirror free?

Principle Mirror is free to download, with no in-app purchases.

### Is Throughline free?

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

### Do Principle Mirror or Throughline have ads?

Neither Principle Mirror nor Throughline shows ads.

### Which is updated more often, Principle Mirror or Throughline?

Principle Mirror ships an update every 2 months, and Throughline every 3 days. Most recently, Principle Mirror was updated on October 24, 2026 and Throughline on October 12, 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.*