# Recall vs Duo Viewer

The clearest difference is in-app purchases: Recall at none against Duo Viewer's 1. Recall also leads on device support (3 vs 1) and iOS requirement (15.6 vs 26.0). On price and ads there is nothing between them.

Both are free to download. Duo Viewer sells 1 one-off in-app purchase. Recall asks for nothing beyond the download.

## The numbers

| Metric | Recall | Duo Viewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (126 ratings)](https://appshunter.io/ios/app/recall-summarize-and-save/id6445893722/reviews)** | — |
| Number of ratings | **126** | — |
| Positive reviews | 53.5% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | — |
| Monetization | Free | — |
| Size | 81 MB | 2 MB |
| Requires iOS | **15.6** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 17+ |
| Developer | [Paul Richards](https://appshunter.io/developer/1674570950) | [Liangjun Song](https://appshunter.io/developer/6816411623) |

## What reviewers say

### Recall

[App page](https://appshunter.io/ios/app/recall-summarize-and-save/id6445893722)

This app creates a personal knowledge base by summarizing online content like videos, articles, and podcasts. It automatically categorizes and links saved summaries, aiding in content discovery and connection. It also employs spaced repetition and active recall techniques to enhance long-term knowledge retention.

**Highlights:** Summarize any online content, Save summaries to personal knowledge base, Automatic categorization of summaries, Automatic linking of related content, Spaced repetition reviews, Active recall testing

**Features:** Vision Pro support

**In-app purchases:** none


### Duo Viewer

[App page](https://appshunter.io/ios/app/duo-viewer/id6816411621)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Duo Viewer Pro | $6.99 | one-time |


## Frequently asked questions

### Is Recall free?

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

### Is Duo Viewer free?

Duo Viewer is free to download, with in-app purchases available.

### Do Recall or Duo Viewer have ads?

Neither Recall nor Duo Viewer shows ads.

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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.*