# CHMate vs ダイヤモンドZAi

The clearest difference is update cadence: CHMate at every 2 weeks against ダイヤモンドZAi's every 15 months. ダイヤモンドZAi's advantage is iOS requirement (9.0 vs 26.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. CHMate sells 1 one-off in-app purchase and ダイヤモンドZAi sells 4 in-app purchases, starting at $7.49 per month. Whichever you choose, the download price is not the number that matters.

CHMate ships an update every 2 weeks, ダイヤモンドZAi every 15 months. The most recent releases landed on October 9, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | CHMate | ダイヤモンドZAi |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.9 (20 ratings)](https://appshunter.io/ios/app/chmate-epub-and-chm-reader/id335157929/reviews)** | — |
| Number of ratings | **20** | — |
| Positive reviews | 55.3% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 15 months |
| Monetization | Free with in-app purchases | — |
| Size | 51 MB | 31 MB |
| Requires iOS | 26.0 | **9.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [贤安 陈](https://appshunter.io/developer/318015371) | [DIAMOND, Inc.](https://appshunter.io/developer/368890276) |

## What reviewers say

### CHMate

[App page](https://appshunter.io/ios/app/chmate-epub-and-chm-reader/id335157929)

This app offers a robust reading experience for EPUB and CHM eBooks. Organize your library, add bookmarks and notes, and customize your reading environment. Share passages and easily search within your books.

**Highlights:** Organize eBooks into collections, Add bookmarks and notes, Customizable fonts and line height, Fast scrolling and pagination, Highlight favorite passages, Built-in search functionality, Share quotes with friends

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| CHMate+ | $9.99 | one-time |

**What reviewers like**

- 👍 Excellent UI/UX design and interface
- 📖 Best CHM file reader available
- ⚡ Fast and smooth performance
- 🎨 Customizable text formatting and fonts
- 🔍 Powerful search functionality

**What reviewers complain about**

- 🐛 Frequent crashes and stability issues
- ⚠️ iCloud sync deletes files irreversibly
- 💰 Expensive pricing for functionality
- 🔄 Highlighting and annotations don't persist
- 📱 Compatibility issues with iOS updates

**Reported bugs**

- App crashes when searching CHM files
- Crashes when using tap-hold for bookmarking
- Highlighting functionality broken after iOS updates
- Notes and bookmarks not saving properly
- Highlights disappear or move between chapters

**Requested features**

- Dark mode and additional color themes (Sepia)
- Book cover display instead of text-only library view
- PDF support
- Text-to-speech functionality
- Better pagination options


### ダイヤモンドZAi

[App page](https://appshunter.io/ios/app/zai/id527508296)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ダイヤモンドZAi | $7.49 | per month |
| ダイヤモンドZAi | $21.49 | per 3 months |
| ダイヤモンドZAi | $37.99 | per 6 months |
| ダイヤモンドZAi | $76.99 | per year |


## Frequently asked questions

### Is CHMate free?

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

### Is ダイヤモンドZAi free?

ダイヤモンドZAi is free to download, with in-app purchases available.

### Do CHMate or ダイヤモンドZAi have ads?

Neither CHMate nor ダイヤモンドZAi shows ads.

### Which is updated more often, CHMate or ダイヤモンドZAi?

CHMate ships an update every 2 weeks, and ダイヤモンドZAi every 15 months. Most recently, CHMate was updated on October 9, 2026 and ダイヤモンドZAi on October 11, 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.*