# Doco Translate vs Second Brain Joiner

The clearest difference is price: Doco Translate at Free against Second Brain Joiner's $3.99. Doco Translate also leads on update cadence (every 5 days vs every 3 weeks). Second Brain Joiner's advantage is in-app purchases (none vs 2). On ads, device support and iOS requirement there is nothing between them.

Doco Translate is free to download; Second Brain Joiner costs $3.99 up front. Doco Translate sells 2 in-app purchases, starting at $2.99 per month. Second Brain Joiner asks for nothing beyond the download.

Doco Translate ships an update every 5 days, Second Brain Joiner every 3 weeks. Both last shipped on October 31, 2026.

## The numbers

| Metric | Doco Translate | Second Brain Joiner |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 5 days** | Every 3 weeks |
| Monetization | — | Paid |
| Size | 63 MB | 11 MB |
| Requires iOS | **18** | 18.2 |
| Devices | **iPhone, iPad, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [欢 颜](https://appshunter.io/developer/1871344320) | [Hirofumi Inoue](https://appshunter.io/developer/1886583968) |

## What reviewers say

### Doco Translate

[App page](https://appshunter.io/ios/app/doco-translate-pdf-translator/id6758205667)

**Features:** Vision Pro support, iPhone Duo support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Doco Translate PRO (Monthly) | $2.99 | per month |
| Doco Translate PRO (Yearly) | $26.99 | per year |


### Second Brain Joiner

[App page](https://appshunter.io/ios/app/second-brain-joiner/id6760870675)

This tool optimizes AI input by merging and formatting Markdown notes. It intelligently filters content, calculates optimal chunk sizes for AI context windows, and maintains original file structure for enhanced AI accuracy and security.

**Highlights:** Advanced filtering by tags and dates, High-precision token calculation, Smart chunking for AI context limits, Local-first absolute security, Folder structure maintenance, Timestamping for context

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

**In-app purchases:** none


## Frequently asked questions

### Is Doco Translate free?

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

### Is Second Brain Joiner free?

Second Brain Joiner costs $3.99, with no in-app purchases.

### Do Doco Translate or Second Brain Joiner have ads?

Neither Doco Translate nor Second Brain Joiner shows ads.

### Which is updated more often, Doco Translate or Second Brain Joiner?

Doco Translate ships an update every 5 days, and Second Brain Joiner every 3 weeks. Most recently, Doco Translate was updated on October 31, 2026 and Second Brain Joiner on October 31, 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.*