# DDx vs WorstFirst

The clearest difference is in-app purchases: WorstFirst at none against DDx's 1. WorstFirst also leads on iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. DDx sells 1 one-off in-app purchase. WorstFirst asks for nothing beyond the download.

## The numbers

| Metric | DDx | WorstFirst |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/worstfirst/id6787245171/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | — | Every 3 months |
| Monetization | — | Free |
| Size | 12 MB | 2 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 17+ | 17+ |
| Developer | [Medicon Apps](https://appshunter.io/developer/307829597) | [Injexa Technologies LLC](https://appshunter.io/developer/6778908051) |

## What reviewers say

### DDx

[App page](https://appshunter.io/ios/app/ddx-differential-diagnosis/id6766528227)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| DDx Pro | $9.99 | one-time |


### WorstFirst

[App page](https://appshunter.io/ios/app/worstfirst/id6787245171)

This decision-tree training tool helps emergency medicine trainees develop critical "rule out the killers first" instincts. It guides users through structured reasoning for various chief complaints, offering teaching pearls and citations to relevant literature. The app is designed for educational use only and functions fully offline.

**Highlights:** Decision-tree training, Rule out killers first instinct, 29 chief-complaint decision trees, Branch-by-branch reasoning, Teaching pearls and pitfalls, Offline functionality

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

**In-app purchases:** none


## Frequently asked questions

### Is DDx free?

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

### Is WorstFirst free?

WorstFirst is free to download, with no in-app purchases.

### Do DDx or WorstFirst have ads?

Neither DDx nor WorstFirst shows ads.

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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.*