# Gravity Machine vs The Keystone

The clearest difference is price: Gravity Machine at $9.99 against The Keystone's $19.99. On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Gravity Machine costs $9.99 and The Keystone $19.99 up front. Neither carries in-app purchases, so what you see is what you pay.

## The numbers

| Metric | Gravity Machine | The Keystone |
| --- | --- | --- |
| Price | **$9.99** | $19.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/gravity-machine/id6761209781/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Weekly | — |
| Monetization | Paid | — |
| Size | 13 MB | 42 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Touchmachines](https://appshunter.io/developer/1887356152) | [artistpro, LLC](https://appshunter.io/developer/1578409515) |

## What reviewers say

### Gravity Machine

[App page](https://appshunter.io/ios/app/gravity-machine/id6761209781)

Create music by manipulating a miniature solar system. Fling orbs that bounce off walls, generating notes based on physics and chosen scales. Customize worlds, sounds, and tunings for unique generative compositions.

**Highlights:** Generative music creation, Physics-based orb interactions, Customizable scales and tunings, Multiple world shapes, AUv3 and standalone modes, MIDI output

**Features:** Vision Pro support

**In-app purchases:** none


### The Keystone

[App page](https://appshunter.io/ios/app/the-keystone/id6821493009)

**In-app purchases:** none


## Frequently asked questions

### Is Gravity Machine free?

Gravity Machine costs $9.99, with no in-app purchases.

### Is The Keystone free?

The Keystone costs $19.99, with no in-app purchases.

### Do Gravity Machine or The Keystone have ads?

Neither Gravity Machine nor The Keystone 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.*