# HAPPY BUILD vs 恺宇 KAIYU

The clearest difference is review sentiment: 恺宇 KAIYU at 67% against HAPPY BUILD's 17%. 恺宇 KAIYU also leads on rating (4.0 vs 3.0). On price, ratings volume, update cadence and ads there is nothing between them.

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

恺宇 KAIYU holds the better App Store score, 4.0 against 3.0. Both are backed by a comparable volume of ratings — 7 and 4 respectively. Written reviews point the same way: 17% of HAPPY BUILD's written reviews are positive against 67% of 恺宇 KAIYU's.

HAPPY BUILD ships an update every 4 weeks, 恺宇 KAIYU fortnightly. The most recent releases landed on October 17, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | HAPPY BUILD | 恺宇 KAIYU |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (7 ratings)](https://appshunter.io/ios/app/happy-build/id1478354576/reviews) | **[4.0 (4 ratings)](https://appshunter.io/ios/app/kaiyu/id1512072697/reviews)** |
| Number of ratings | **7** | 4 |
| Positive reviews | 16.7% of reviews | **66.7% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 weeks | **Fortnightly** |
| Monetization | Free | Free |
| Size | 375 MB | 233 MB |
| Requires iOS | 9.0 | 9.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [睦彬 王](https://appshunter.io/developer/1259740025) | [植川 马](https://appshunter.io/developer/1783803021) |

## What reviewers say

### HAPPY BUILD

[App page](https://appshunter.io/ios/app/happy-build/id1478354576)

Control Xinyu Bluetooth toy cars with your mobile device. Offers multiple control methods like buttons, gyroscope, voice commands, and programming for varied play experiences.

**Highlights:** Bluetooth connectivity, Multiple control modes, Gyroscope control, Voice command control, Action programming

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

**In-app purchases:** none


### 恺宇 KAIYU

[App page](https://appshunter.io/ios/app/kaiyu/id1512072697)

This app offers diverse control methods for an engaging experience. Explore options like button remotes, gyroscope control, route drawing, voice commands, and custom graphical programming.

**Highlights:** Multiple control styles, Button remote, Gyroscope control, Route drawing, Voice command control, Custom graphical programming

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is HAPPY BUILD free?

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

### Is 恺宇 KAIYU free?

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

### Which has better reviews, HAPPY BUILD or 恺宇 KAIYU?

恺宇 KAIYU is rated higher. HAPPY BUILD averages 3.0 out of 5 from 7 ratings, while 恺宇 KAIYU averages 4.0 from 4 ratings.

### Do HAPPY BUILD or 恺宇 KAIYU have ads?

Neither HAPPY BUILD nor 恺宇 KAIYU shows ads.

### Which is updated more often, HAPPY BUILD or 恺宇 KAIYU?

HAPPY BUILD ships an update every 4 weeks, and 恺宇 KAIYU fortnightly. Most recently, HAPPY BUILD was updated on October 17, 2026 and 恺宇 KAIYU on October 8, 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.*