# OpenViewer vs ctLibrary

The clearest difference is ads: ctLibrary at none against OpenViewer's shown. ctLibrary also leads on update cadence (daily vs every 2 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

OpenViewer ships an update every 2 months, ctLibrary daily. The most recent releases landed on September 15, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | OpenViewer | ctLibrary |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | **Daily** |
| Size | 41 MB | 43 MB |
| Requires iOS | **15.1** | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [BongJun Park](https://appshunter.io/developer/1887269135) | [CozziTech LLC](https://appshunter.io/developer/1881303395) |

## What reviewers say

### OpenViewer

[App page](https://appshunter.io/ios/app/openviewer/id6763845346)

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

**In-app purchases:** none


### ctLibrary

[App page](https://appshunter.io/ios/app/ctlibrary/id6773506408)

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

**In-app purchases:** none


## Frequently asked questions

### Is OpenViewer free?

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

### Is ctLibrary free?

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

### Do OpenViewer or ctLibrary have ads?

OpenViewer shows ads; ctLibrary does not.

### Which is updated more often, OpenViewer or ctLibrary?

OpenViewer ships an update every 2 months, and ctLibrary daily. Most recently, OpenViewer was updated on September 15, 2026 and ctLibrary on September 19, 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.*