# Second Brain vs Estratum

The clearest difference is update cadence: Estratum at daily against Second Brain's every 9 days. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Second Brain sells 2 in-app purchases, starting at $4.99 per month and Estratum sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Second Brain ships an update every 9 days, Estratum daily. The most recent releases landed on October 10, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Second Brain | Estratum |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (2 ratings)](https://appshunter.io/ios/app/second-brain-know-yourself/id6760254340/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 9 days | **Daily** |
| Monetization | Freemium | — |
| Size | 12 MB | 28 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Liwei Xie](https://appshunter.io/developer/1106616046) | [LyXeoN](https://appshunter.io/developer/566849105) |

## What reviewers say

### Second Brain

[App page](https://appshunter.io/ios/app/second-brain-know-yourself/id6760254340)

This AI-powered journal captures your thoughts via voice or text, automatically organizing and connecting them. It helps you recall memories, discover patterns, and reflect on your growth.

**Highlights:** AI classification, tagging, and summarization, Semantic search by meaning, Three-layer memory system, People cards for relationship tracking, Weekly AI reflections, Voice input with transcription, Data export (JSON + Markdown)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Second Brain Pro | $4.99 | per month |
| Second Brain Pro | $39.99 | per year |


### Estratum

[App page](https://appshunter.io/ios/app/estratum-second-brain/id6795179990)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Estratum Pro — Lifetime | $24.99 | one-time |


## Frequently asked questions

### Is Second Brain free?

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

### Is Estratum free?

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

### Do Second Brain or Estratum have ads?

Neither Second Brain nor Estratum shows ads.

### Which is updated more often, Second Brain or Estratum?

Second Brain ships an update every 9 days, and Estratum daily. Most recently, Second Brain was updated on October 10, 2026 and Estratum on October 1, 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.*