# iobook vs Moss

The clearest difference is in-app purchases: Moss at none against iobook's 2. Moss also leads on update cadence (every 5 days vs every 3 weeks) and iOS requirement (15.1 vs 18.0). On price, ads and device support there is nothing between them.

Both are free to download. iobook sells 2 in-app purchases, starting at $1.99 per month. Moss asks for nothing beyond the download.

iobook ships an update every 3 weeks, Moss every 5 days. The most recent releases landed on September 25, 2026 and July 4, 2026 respectively.

## The numbers

| Metric | iobook | Moss |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 5 days** |
| Size | 6 MB | 40 MB |
| Requires iOS | 18.0 | **15.1** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Joonhee Cho](https://appshunter.io/developer/1124471697) | [Yemin Lee](https://appshunter.io/developer/1811919257) |

## What reviewers say

### iobook

[App page](https://appshunter.io/ios/app/iobook/id6742841375)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Basic (Monthly) | $1.99 | per month |
| Basic (Yearly) | $19.99 | per year |


### Moss

[App page](https://appshunter.io/ios/app/moss/id6760577624)

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

**In-app purchases:** none


## Frequently asked questions

### Is iobook free?

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

### Is Moss free?

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

### Do iobook or Moss have ads?

Neither iobook nor Moss shows ads.

### Which is updated more often, iobook or Moss?

iobook ships an update every 3 weeks, and Moss every 5 days. Most recently, iobook was updated on September 25, 2026 and Moss on July 4, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*