# Ook for Books vs ShelfMark

The clearest difference is in-app purchases: Ook for Books at none against ShelfMark's 1. Ook for Books also leads on update cadence (every 3 days vs weekly). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. ShelfMark sells 1 one-off in-app purchase. Ook for Books asks for nothing beyond the download.

Ook for Books ships an update every 3 days, ShelfMark weekly. Both last shipped on October 31, 2026.

## The numbers

| Metric | Ook for Books | ShelfMark |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 days** | Weekly |
| Size | 8 MB | 6 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 12+ | 4+ |
| Developer | [Jung Suk Hahn](https://appshunter.io/developer/1869893041) | [InnovaLabWorks](https://appshunter.io/developer/1888514726) |

## What reviewers say

### Ook for Books

[App page](https://appshunter.io/ios/app/ook-for-books/id6757951712)

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

**In-app purchases:** none


### ShelfMark

[App page](https://appshunter.io/ios/app/shelfmark-reading-tracker/id6788129809)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ShelfMark Lifetime | $49.99 | one-time |


## Frequently asked questions

### Is Ook for Books free?

Ook for Books is free to download, with no in-app purchases.

### Is ShelfMark free?

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

### Do Ook for Books or ShelfMark have ads?

Neither Ook for Books nor ShelfMark shows ads.

### Which is updated more often, Ook for Books or ShelfMark?

Ook for Books ships an update every 3 days, and ShelfMark weekly. Most recently, Ook for Books was updated on October 31, 2026 and ShelfMark on October 31, 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.*