# Diagnosaurus® DDx vs FP Notebook

The clearest difference is monetization model: Diagnosaurus® DDx at free with in-app purchases against FP Notebook's subscription. FP Notebook's advantage is update cadence (every 2 months vs every 10 months) and chart position (#51 vs unranked). On price, rating, review sentiment and ratings volume there is nothing between them.

Both are free to download. Diagnosaurus® DDx sells 1 one-off in-app purchase and FP Notebook sells 3 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 4.8 for Diagnosaurus® DDx against 4.8 for FP Notebook. Both are backed by a comparable volume of ratings — 2.5K and 3.3K respectively. Written reviews are what separate them: 53% of Diagnosaurus® DDx's written reviews are positive against 58% of FP Notebook's.

Diagnosaurus® DDx ships an update every 10 months, FP Notebook every 2 months. The most recent releases landed on September 24, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | Diagnosaurus® DDx | FP Notebook |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (2.5K ratings)](https://appshunter.io/ios/app/diagnosaurus-ddx/id833728910/reviews) | [4.8 (3.3K ratings)](https://appshunter.io/ios/app/fp-notebook/id835973313/reviews) |
| Number of ratings | 2.5K | **3.3K** |
| Positive reviews | 53.2% of reviews | **58.2% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 10 months | **Every 2 months** |
| Monetization | **Free with in-app purchases** | Subscription |
| Best chart rank | — | **#51** |
| Size | 18 MB | 134 MB |
| Requires iOS | 15.0 | **14.3** |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 17+ | 17+ |
| Developer | [Unbound Medicine, Inc.](https://appshunter.io/developer/300420400) | [Atmosphere Apps, Inc.](https://appshunter.io/developer/334077424) |

## What reviewers say

### Diagnosaurus® DDx

[App page](https://appshunter.io/ios/app/diagnosaurus-ddx/id833728910)

This medical reference tool assists healthcare professionals in performing differential diagnoses quickly and confidently. It offers a searchable database of over 1,000 diagnoses, cross-referenced for related conditions, and allows users to save favorite entries and make custom notes.

**Highlights:** Over 1,000 differential diagnoses, Search by organ system, symptom, or disease, See Related DDx feature, Save favorite entries, Highlight and make custom notes, Universal Index Search

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Diagnosaurus DDx | $4.99 | one-time |

**What reviewers like**

- 👍 User-friendly interface
- 🚀 Quick access to differential diagnoses
- 💡 Helpful for building differential diagnoses
- 👍 Comprehensive coverage of conditions
- 👍 Useful for medical students and practitioners

**What reviewers complain about**

- 🐛 Lack of in-depth information
- 🐛 Incomplete differential diagnoses
- 🐛 Lack of links to explain conditions
- 🐛 Requires in-app purchase to access full content
- 🐛 Unreliable update mechanism

**Reported bugs**

- Subscription issues and inability to restore purchases
- Blank pages and non-functional content
- Compatibility issues with newer iOS versions

**Requested features**

- Add ability to edit or add custom differential diagnoses
- Improve search functionality and navigation
- Provide more detailed information on conditions
- Integrate with other medical resources and databases
- Improve support for older devices and iOS versions


### FP Notebook

[App page](https://appshunter.io/ios/app/fp-notebook/id835973313)

**Currently charting:** #51 Top Grossing · Medical (US App Store)

A comprehensive medical reference for primary care and emergency clinicians, offering rapid access to over 6100 interlinked topic pages. Content is updated monthly through literature reviews and conferences, providing up-to-date information for medical professionals.

**Highlights:** Rapid access medical reference, Over 6100 interlinked topic pages, Content updated monthly, 31 specialty books, 700+ chapters, Point-of-care tool

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Subscription | $1.99 | per month |
| Annual Subscription | $19.99 | per year |
| Annual Sub | $24.99 | per year |

**What reviewers like**

- 🌟 Excellent, comprehensive medical reference
- ⚡️ Efficient, concise, and easy to use
- 🧠 Invaluable for medical students, residents, and practitioners
- 🤝 Highly recommended by users
- 🕰️ Frequently used and relied upon for years

**What reviewers complain about**

- 💰 Subscription model frustrates some users who previously had free access
- 🐞 Occasional app freezing or crashing issues reported
- 🔍 Built-in search function could be improved

**Reported bugs**

- App freezing or crashing on certain devices
- Subscription issues or unexpected charges

**Requested features**

- Ability to earn continuing education credits through the app
- Improved search functionality


## Frequently asked questions

### Is Diagnosaurus® DDx free?

Diagnosaurus® DDx is free to download, with in-app purchases available.

### Is FP Notebook free?

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

### Which has better reviews, Diagnosaurus® DDx or FP Notebook?

Diagnosaurus® DDx and FP Notebook are both rated 4.8 out of 5 on the App Store, from 2.5K and 3.3K ratings respectively.

### Do Diagnosaurus® DDx or FP Notebook have ads?

Neither Diagnosaurus® DDx nor FP Notebook shows ads.

### Which is updated more often, Diagnosaurus® DDx or FP Notebook?

Diagnosaurus® DDx ships an update every 10 months, and FP Notebook every 2 months. Most recently, Diagnosaurus® DDx was updated on September 24, 2026 and FP Notebook on September 23, 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.*