# Mugen AI vs 返信どうする？AI添削・敬語翻訳・言い換えツール

The clearest difference is in-app purchases: Mugen AI at none against 返信どうする？AI添削・敬語翻訳・言い換えツール's 1. On price, review sentiment, update cadence and ads there is nothing between them.

Both are free to download. 返信どうする？AI添削・敬語翻訳・言い換えツール sells 1 in-app purchase, starting at $1.99 per month. Mugen AI asks for nothing beyond the download.

Mugen AI ships an update every 3 weeks, 返信どうする？AI添削・敬語翻訳・言い換えツール every 4 weeks. The most recent releases landed on November 8, 2026 and November 7, 2026 respectively.

## The numbers

| Metric | Mugen AI | 返信どうする？AI添削・敬語翻訳・言い換えツール |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 3 weeks** | Every 4 weeks |
| Monetization | **Ad-supported** | Freemium |
| Size | 10 MB | 6 MB |
| Requires iOS | 18.0 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Koichiro Kamada](https://appshunter.io/developer/476534292) | [Appricot Co.,Ltd.](https://appshunter.io/developer/1716553156) |

## What reviewers say

### Mugen AI

[App page](https://appshunter.io/ios/app/mugen-ai/id6740717908)

This AI assistant app makes advanced artificial intelligence accessible to everyone with a simple, intuitive interface. It offers over 10 practical AI functions, including translation, summarization, and idea generation, requiring no prior technical knowledge.

**Highlights:** Intuitive AI interface, Translation in multiple languages, Text summarization, Grammar and style correction, Idea generation, Question answering

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

**In-app purchases:** none


### 返信どうする？AI添削・敬語翻訳・言い換えツール

[App page](https://appshunter.io/ios/app/ai/id6741709838)

AI-powered tool to generate replies for various messages, from social media to business emails. It automatically detects the context and adjusts the tone, ensuring natural-sounding responses. Also offers proofreading and screenshot text extraction for convenience.

**Highlights:** AI-generated replies, Automatic context detection, Natural text formatting, Draft proofreading, Screenshot text extraction, Reply history and adjustment

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Monthly Plan | $1.99 | per month |


## Frequently asked questions

### Is Mugen AI free?

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

### Is 返信どうする？AI添削・敬語翻訳・言い換えツール free?

返信どうする？AI添削・敬語翻訳・言い換えツール is free to download, with in-app purchases available.

### Do Mugen AI or 返信どうする？AI添削・敬語翻訳・言い換えツール have ads?

Both Mugen AI and 返信どうする？AI添削・敬語翻訳・言い換えツール show ads.

### Which is updated more often, Mugen AI or 返信どうする？AI添削・敬語翻訳・言い換えツール?

Mugen AI ships an update every 3 weeks, and 返信どうする？AI添削・敬語翻訳・言い換えツール every 4 weeks. Most recently, Mugen AI was updated on November 8, 2026 and 返信どうする？AI添削・敬語翻訳・言い換えツール on November 7, 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.*