# Udan HESS vs SkyEye

The clearest difference is update cadence: SkyEye at every 3 weeks against Udan HESS's every 3 months. On price, ads, in-app purchases and device support there is nothing between them.

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

Udan HESS ships an update every 3 months, SkyEye every 3 weeks. The most recent releases landed on September 10, 2026 and May 15, 2026 respectively.

## The numbers

| Metric | Udan HESS | SkyEye |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Size | 33 MB | 48 MB |
| Requires iOS | 13.0 | **12.0** |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Anhui Udan Technology Co., Ltd.](https://appshunter.io/developer/1593792520) | [Hangzhou Huading New Energy Co., Ltd.](https://appshunter.io/developer/1728558849) |

## What reviewers say

### Udan HESS

[App page](https://appshunter.io/ios/app/udan-hess/id6443758347)

**Features:** macOS Compatibility

**In-app purchases:** none


### SkyEye

[App page](https://appshunter.io/ios/app/skyeye/id6477121811)

**In-app purchases:** none


## Frequently asked questions

### Is Udan HESS free?

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

### Is SkyEye free?

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

### Do Udan HESS or SkyEye have ads?

Neither Udan HESS nor SkyEye shows ads.

### Which is updated more often, Udan HESS or SkyEye?

Udan HESS ships an update every 3 months, and SkyEye every 3 weeks. Most recently, Udan HESS was updated on September 10, 2026 and SkyEye on May 15, 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.*