# FormKey vs ThermVoltTube

The clearest difference is iOS requirement: ThermVoltTube at 16.0 against FormKey's 18.6. On price, ads, in-app purchases and device support there is nothing between them.

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

## The numbers

| Metric | FormKey | ThermVoltTube |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (8 ratings)](https://appshunter.io/ios/app/formkey/id1535350561/reviews)** | — |
| Number of ratings | **8** | — |
| Positive reviews | 57.1% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Fortnightly | — |
| Monetization | Paid | — |
| Size | 88 MB | 27 MB |
| Requires iOS | 18.6 | **16.0** |
| Devices | iPad | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Polyhedra](https://appshunter.io/developer/1535350563) | [Shoma Kondo](https://appshunter.io/developer/1884832972) |

## What reviewers say

### FormKey

[App page](https://appshunter.io/ios/app/formkey/id1535350561)

This app is an intuitive MIDI controller that helps musicians improve by using shapes for notes and colors for octaves. Its unique isomorphic keys aid in pattern recognition and chord discovery, making music creation more accessible.

**Highlights:** Shape-based note input, Color-coded octaves, Isomorphic key layout, Pattern recognition aid, Chord discovery assistance, Future update commitment

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| FormKey Full Unlock | $14.99 | one-time |


### ThermVoltTube

[App page](https://appshunter.io/ios/app/thermvolttube/id6777901033)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ThermVoltTube Full Version | $4.99 | one-time |


## Frequently asked questions

### Is FormKey free?

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

### Is ThermVoltTube free?

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

### Do FormKey or ThermVoltTube have ads?

Neither FormKey nor ThermVoltTube shows ads.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*