# SonnetAI vs Sigma Domain

The clearest difference is update cadence: Sigma Domain at every 2 days against SonnetAI's every 9 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. SonnetAI sells 4 in-app purchases, starting at $25.00 per month and Sigma Domain sells 2 in-app purchases, starting at $5.99 per month. Whichever you choose, the download price is not the number that matters.

SonnetAI ships an update every 9 months, Sigma Domain every 2 days. The most recent releases landed on October 14, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | SonnetAI | Sigma Domain |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/sonnetai/id6747341249/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 9 months | **Every 2 days** |
| Monetization | Free with in-app purchases | — |
| Size | 40 MB | 73 MB |
| Requires iOS | **15.1** | 16.6 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [AAARK Ventures LLC](https://appshunter.io/developer/1774364339) | [Sigma Domain](https://appshunter.io/developer/1876019749) |

## What reviewers say

### SonnetAI

[App page](https://appshunter.io/ios/app/sonnetai/id6747341249)

This app transforms conversations into insightful, customizable notes with advanced features like concept maps and tailored templates. It helps users track relationships and build a knowledge asset that evolves over time.

**Highlights:** AI-powered insights, Customizable notes, Concept maps, Tailored templates, Relationship tracking, Evolving knowledge asset

**Features:** macOS Compatibility

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Plus Subscription. | $25.00 | per month |
| Pro Subscriptions | $35.00 | per month |
| Plus Annual Subscriptions | $179.99 | per year |
| Pro Annual Subscriptions | $239.99 | per year |


### Sigma Domain

[App page](https://appshunter.io/ios/app/sigma-domain/id6751211704)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Standard Monthly Sigma Domain | $5.99 | per month |
| Additional Usage - Sigma Domain | $9.99 | one-time |


## Frequently asked questions

### Is SonnetAI free?

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

### Is Sigma Domain free?

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

### Do SonnetAI or Sigma Domain have ads?

Neither SonnetAI nor Sigma Domain shows ads.

### Which is updated more often, SonnetAI or Sigma Domain?

SonnetAI ships an update every 9 months, and Sigma Domain every 2 days. Most recently, SonnetAI was updated on October 14, 2026 and Sigma Domain on October 28, 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.*