# CleanAirOptima vs Furigana Keyboard Ruby IME

The clearest difference is price: CleanAirOptima at Free against Furigana Keyboard Ruby IME's $0.49. CleanAirOptima also leads on iOS requirement (12.0 vs 18.0). Furigana Keyboard Ruby IME's advantage is update cadence (every 2 days vs every 17 months). On ads, in-app purchases and device support there is nothing between them.

CleanAirOptima is free to download; Furigana Keyboard Ruby IME costs $0.49 up front. Neither carries in-app purchases, so what you see is what you pay.

CleanAirOptima ships an update every 17 months, Furigana Keyboard Ruby IME every 2 days. The most recent releases landed on October 6, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | CleanAirOptima | Furigana Keyboard Ruby IME |
| --- | --- | --- |
| Price | **Free** | $0.49 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 17 months | **Every 2 days** |
| Size | 194 MB | 104 MB |
| Requires iOS | **12.0** | 18.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Clean Air Optima International B.V.](https://appshunter.io/developer/1597731229) | [HIFUMI](https://appshunter.io/developer/1792252763) |

## What reviewers say

### CleanAirOptima

[App page](https://appshunter.io/ios/app/cleanairoptima/id1597731227)

**Features:** macOS Compatibility

**In-app purchases:** none


### Furigana Keyboard Ruby IME

[App page](https://appshunter.io/ios/app/furigana-keyboard-ruby-ime/id6765480716)

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

**In-app purchases:** none


## Frequently asked questions

### Is CleanAirOptima free?

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

### Is Furigana Keyboard Ruby IME free?

Furigana Keyboard Ruby IME costs $0.49, with no in-app purchases.

### Do CleanAirOptima or Furigana Keyboard Ruby IME have ads?

Neither CleanAirOptima nor Furigana Keyboard Ruby IME shows ads.

### Which is updated more often, CleanAirOptima or Furigana Keyboard Ruby IME?

CleanAirOptima ships an update every 17 months, and Furigana Keyboard Ruby IME every 2 days. Most recently, CleanAirOptima was updated on October 6, 2026 and Furigana Keyboard Ruby IME on October 17, 2026.

---

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