# ココタン vs Boost.AI 英作文添削・共通テスト英語

The clearest difference is in-app purchases: ココタン at none against Boost.AI 英作文添削・共通テスト英語's 3. On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Boost.AI 英作文添削・共通テスト英語 sells 3 in-app purchases, starting at $5.99 per month. ココタン asks for nothing beyond the download.

ココタン ships an update every 3 days, Boost.AI 英作文添削・共通テスト英語 every 4 days. The most recent releases landed on October 2, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | ココタン | Boost.AI 英作文添削・共通テスト英語 |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 90.5% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 days** | Every 4 days |
| Monetization | — | Freemium |
| Size | 82 MB | 143 MB |
| Requires iOS | 14.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [KOKOMIRAI, K.K.](https://appshunter.io/developer/1663398018) | [ATSUSHI KIMURA](https://appshunter.io/developer/1829870349) |

## What reviewers say

### ココタン

[App page](https://appshunter.io/ios/app/id6642667955)

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

**In-app purchases:** none


### Boost.AI 英作文添削・共通テスト英語

[App page](https://appshunter.io/ios/app/boostai/id6749287559)

This AI-powered app offers instant English writing feedback, detailed explanations, and AI chat for deeper understanding. It supports various writing styles and learning goals, helping users improve their English proficiency anytime, anywhere.

**Highlights:** Instant AI essay correction, Detailed explanations for errors, Handwriting recognition for essays, AI chat for clarification, Learning history management, Diverse question formats, Flashcards and English news

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Boost Pro 月額プラン | $5.99 | per month |
| 3ヶ月 | $11.99 | per 3 months |
| Boost Pro 年額プラン | $39.99 | per year |


## Frequently asked questions

### Is ココタン free?

ココタン is free to download, with no in-app purchases.

### Is Boost.AI 英作文添削・共通テスト英語 free?

Boost.AI 英作文添削・共通テスト英語 is free to download, with in-app purchases available.

### Do ココタン or Boost.AI 英作文添削・共通テスト英語 have ads?

Neither ココタン nor Boost.AI 英作文添削・共通テスト英語 shows ads.

### Which is updated more often, ココタン or Boost.AI 英作文添削・共通テスト英語?

ココタン ships an update every 3 days, and Boost.AI 英作文添削・共通テスト英語 every 4 days. Most recently, ココタン was updated on October 2, 2026 and Boost.AI 英作文添削・共通テスト英語 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.*