# FourKeys vs Engine Sound

FourKeys and Engine Sound are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Both are free to download. FourKeys sells 1 one-off in-app purchase and Engine Sound sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

## The numbers

| Metric | FourKeys | Engine Sound |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 66.7% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 9 days | — |
| Monetization | Free with in-app purchases | — |
| Size | 23 MB | 5 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | **iPhone, Apple Watch** | iPhone |
| Age rating | 9+ | 4+ |
| Developer | [敏刚 易](https://appshunter.io/developer/1872259103) | [Yuya Suzuki](https://appshunter.io/developer/1882402717) |

## What reviewers say

### FourKeys

[App page](https://appshunter.io/ios/app/fourkeys-sound-button/id6761699602)

Tap large buttons to play funny sound effects instantly. Create custom soundboards with your own recordings or imported audio. Enjoy this satisfying sound toy on your iPhone, Apple Watch, and home screen widget for pranks or stress relief.

**Highlights:** Instant sound effect playback, Customizable soundboards, Record and import audio, iPhone and Apple Watch support, Interactive home screen widget, Shareable keyboard packs

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| FourKeys Unlimited | $1.99 | one-time |


### Engine Sound

[App page](https://appshunter.io/ios/app/engine-sound/id6816795459)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| All Engines | $0.99 | one-time |


## Frequently asked questions

### Is FourKeys free?

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

### Is Engine Sound free?

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

### Do FourKeys or Engine Sound have ads?

Neither FourKeys nor Engine Sound shows ads.

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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.*