# Mast'O vs MCAS Tracker

The clearest difference is in-app purchases: Mast'O at none against MCAS Tracker's 10. MCAS Tracker's advantage is update cadence (every 6 months vs every 14 months) and device support (4 vs 2). On price, ads and iOS requirement there is nothing between them.

Both are free to download. MCAS Tracker sells 10 in-app purchases, starting at $7.99 per 7 days. Mast'O asks for nothing beyond the download.

Mast'O ships an update every 14 months, MCAS Tracker every 6 months. The most recent releases landed on November 8, 2026 and November 1, 2026 respectively.

## The numbers

| Metric | Mast'O | MCAS Tracker |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.4 (21 ratings)](https://appshunter.io/ios/app/mcas-tracker/id6754931863/reviews)** |
| Number of ratings | — | **21** |
| Positive reviews | — | 75.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 14 months | **Every 6 months** |
| Monetization | — | Free with in-app purchases |
| Size | 27 MB | 238 MB |
| Requires iOS | **15.0** | 15.5 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 12+ | 4+ |
| Developer | [Filière MaRIH](https://appshunter.io/developer/1727106794) | [Digital Therapeutics](https://appshunter.io/developer/1721663167) |

## What reviewers say

### Mast'O

[App page](https://appshunter.io/ios/app/masto/id6476554444)

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

**In-app purchases:** none


### MCAS Tracker

[App page](https://appshunter.io/ios/app/mcas-tracker/id6754931863)

This app helps individuals manage Mast Cell Activation Syndrome by tracking symptoms, food intake, and environmental triggers. It offers advanced analytics to identify patterns and provides secure, exportable reports for healthcare providers. The app aims to offer clarity and actionable insights for better health management.

**Highlights:** Symptom tracking (hives, itching, flushing), Food and supplement logging, Trigger identification (environmental, emotional), Advanced analytics and correlation analysis, Medication tracking, Daily health journal, Secure, exportable reports

**Features:** macOS Compatibility, Siri integration, Apple Watch app, iMessage stickers, Vision Pro support

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| easy pass | $7.99 | per 7 days |
| flex pass | $12.99 | per month |
| carey ai max | $19.99 | per month |
| carey ai ultra | $29.99 | per month |
| plus | $29.99 | per year |
| limited discount | $34.99 | per year |
| yearly access | $39.99 | per year |
| Extended Trial | $39.99 | per year |
| carey ai credits | $8.99 | one-time |
| lifetime upgrade | $119.99 | one-time |


## Frequently asked questions

### Is Mast'O free?

Mast'O is free to download, with no in-app purchases.

### Is MCAS Tracker free?

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

### Do Mast'O or MCAS Tracker have ads?

Neither Mast'O nor MCAS Tracker shows ads.

### Which is updated more often, Mast'O or MCAS Tracker?

Mast'O ships an update every 14 months, and MCAS Tracker every 6 months. Most recently, Mast'O was updated on November 8, 2026 and MCAS Tracker on November 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.*