# Watto vs 21energy

The clearest difference is in-app purchases: 21energy at none against Watto's 4. 21energy also leads on update cadence (fortnightly vs every 2 months) and iOS requirement (15.0 vs 18.0). On price, ads and device support there is nothing between them.

Both are free to download. Watto sells 4 one-off in-app purchases. 21energy asks for nothing beyond the download.

Watto ships an update every 2 months, 21energy fortnightly. The most recent releases landed on October 25, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | Watto | 21energy |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 16.7% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 months | **Fortnightly** |
| Monetization | — | Free |
| Size | 4 MB | 43 MB |
| Requires iOS | 18.0 | **15.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Erik Aigner](https://appshunter.io/developer/422975586) | [21energy GmbH](https://appshunter.io/developer/1741551485) |

## What reviewers say

### Watto

[App page](https://appshunter.io/ios/app/watto/id6462795022)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Small Tip | $0.99 | one-time |
| Medium Tip | $2.99 | one-time |
| Large Tip | $3.99 | one-time |
| Extra Large Tip | $8.99 | one-time |


### 21energy

[App page](https://appshunter.io/ios/app/21energy/id6497953701)

Easily set up and configure your Ofen and Ofen Pro heaters. Connect your device via Bluetooth to your local WiFi and manage your mining pool settings with just a few taps.

**Highlights:** Easy setup and configuration, Bluetooth connectivity, WiFi connection, Mining pool configuration, Ofen and Ofen Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Watto free?

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

### Is 21energy free?

21energy is free to download, with no in-app purchases.

### Do Watto or 21energy have ads?

Neither Watto nor 21energy shows ads.

### Which is updated more often, Watto or 21energy?

Watto ships an update every 2 months, and 21energy fortnightly. Most recently, Watto was updated on October 25, 2026 and 21energy on October 20, 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.*