# KaiShui vs WaveFast

The clearest difference is monetization model: WaveFast at free against KaiShui's freemium. KaiShui's advantage is update cadence (every 9 days vs every 3 weeks). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. KaiShui sells 4 in-app purchases, starting at $1.99 per month and WaveFast sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

KaiShui ships an update every 9 days, WaveFast every 3 weeks. Both last shipped on October 31, 2026.

## The numbers

| Metric | KaiShui | WaveFast |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/wavefast-fasting-tracker/id6764770817/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 9 days** | Every 3 weeks |
| Monetization | Freemium | **Free** |
| Size | 214 MB | 20 MB |
| Requires iOS | 17.6 | 17.6 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 9+ |
| Developer | [凌峰 高](https://appshunter.io/developer/1887860748) | [瑞华 张](https://appshunter.io/developer/1608130007) |

## What reviewers say

### KaiShui

[App page](https://appshunter.io/ios/app/kaishui-brown-noise-and-tracker/id6761164087)

Craft personalized sleep soundscapes with a smart mixing engine and track your sleep stages. Enjoy seamless integration with iOS features like Live Activities and Siri for ultimate control over your rest.

**Highlights:** 10-Track Smart Mixing Engine, Live Activities & Dynamic Island integration, HealthKit sleep stage and heart rate analysis, Siri and Automation support, All-format audio import (MP3, M4A, FLAC), iCloud backup for cross-device syncing

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| KaiShui VIP Monthly | $1.99 | per month |
| Annual | $14.99 | per year |
| Kaishui VIP - Lifetime Early Bird | $14.99 | one-time |
| KaiShui VIP Lifetime | $29.99 | one-time |


### WaveFast

[App page](https://appshunter.io/ios/app/wavefast-fasting-tracker/id6764770817)

Track your intermittent fasting with a visually engaging and user-friendly interface. This app offers a one-time purchase, no subscriptions, and prioritizes user privacy by storing all data locally. Stay motivated with fluid animations and smart notifications.

**Highlights:** Mesmerizing fluid wave animation, Dynamic Island & Live Activities integration, History and streak tracking, Customizable water themes, Body status insights, Smart notifications, Privacy-focused local data storage

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| WaveFast Pro | $5.99 | one-time |


## Frequently asked questions

### Is KaiShui free?

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

### Is WaveFast free?

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

### Do KaiShui or WaveFast have ads?

Neither KaiShui nor WaveFast shows ads.

### Which is updated more often, KaiShui or WaveFast?

KaiShui ships an update every 9 days, and WaveFast every 3 weeks. Most recently, KaiShui was updated on October 31, 2026 and WaveFast on October 31, 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.*