# N'Back Butterfly vs Eri.cards

The clearest difference is ads: Eri.cards at none against N'Back Butterfly's shown. On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

## The numbers

| Metric | N'Back Butterfly | Eri.cards |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 10 months | — |
| Monetization | Ad-supported | — |
| Size | 9 MB | 2 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Yasuyoshi Ota](https://appshunter.io/developer/1500357652) | [Sergey Rumyantsev](https://appshunter.io/developer/1714686825) |

## What reviewers say

### N'Back Butterfly

[App page](https://appshunter.io/ios/app/nback-butterfly/id853507894)

Enhance your cognitive abilities and combat forgetfulness with this application designed to improve working memory. It utilizes the scientifically recognized n-back task to train your brain's capacity for information recall and manipulation.

**Highlights:** Working memory improvement, N-back task training, Cognitive neuroscience assessment, Continuous performance task

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

**In-app purchases:** none


### Eri.cards

[App page](https://appshunter.io/ios/app/ericards/id6471030786)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is N'Back Butterfly free?

N'Back Butterfly is free to download, with no in-app purchases.

### Is Eri.cards free?

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

### Do N'Back Butterfly or Eri.cards have ads?

N'Back Butterfly shows ads; Eri.cards does not.

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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.*