# CASSY App vs phyphox

The clearest difference is review sentiment: phyphox at 79% against CASSY App's 60%. phyphox also leads on iOS requirement (12.0 vs 15.0). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Both ship on a similar rhythm, roughly every 3 months. Both last shipped on October 24, 2026.

## The numbers

| Metric | CASSY App | phyphox |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.6 (280 ratings)](https://appshunter.io/ios/app/phyphox/id1127319693/reviews)** |
| Number of ratings | — | **280** |
| Positive reviews | 60.0% of reviews | **78.7% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | Every 3 months |
| Monetization | Free | Free |
| Size | 76 MB | 19 MB |
| Requires iOS | 15.0 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [LD DIDACTIC GmbH](https://appshunter.io/developer/1083056850) | [RWTH Aachen University](https://appshunter.io/developer/371466796) |

## What reviewers say

### CASSY App

[App page](https://appshunter.io/ios/app/cassy-app/id1083056851)

Control scientific measurement devices and display data on your mobile device. Analyze, store, and share results without a PC. Supports a wide range of physics, chemistry, and biology sensors.

**Highlights:** Control CASSY devices, Display measurements (analog/digital, tables, diagrams), Evaluate and store data, Share results wirelessly, Support for physics, chemistry, and biology sensors, WebDAV server integration

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

**In-app purchases:** none


### phyphox

[App page](https://appshunter.io/ios/app/phyphox/id1127319693)

Unlock your phone's sensors for scientific exploration. Conduct pre-built experiments or create your own using accelerometers, magnetometers, and more. Analyze and export data in various formats for further study.

**Highlights:** Pre-defined experiments, Data export (CSV, TSV, Excel), Web-based remote control, Custom experiment editor, Access to phone sensors, Advanced analysis functions

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

**In-app purchases:** none

**What reviewers like**

- 💡 Access to phone sensors
- 🔬 Useful for physics experiments
- 📊 Data logging and export
- 🆓 Free and no ads
- 🤔 Sparks curiosity

**What reviewers complain about**

- 🐛 Bugs and crashes
- 📉 Inconsistent performance
- 🔒 App locks/minimizes recording
- ❓ Units not always clear
- ⚠️ Potential for device damage

**Reported bugs**

- App crashes on older devices
- Barometer not working on iOS 17.4
- Network error: Generic error
- Sound measurement curve disappears
- App crashes frequently

**Requested features**

- Add infrasound detector
- More units of measurement (G-force, PSI, feet)
- NFC/RFID support
- In-app bug report feature
- Allow other sensors via USB-C


## Frequently asked questions

### Is CASSY App free?

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

### Is phyphox free?

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

### Do CASSY App or phyphox have ads?

Neither CASSY App nor phyphox shows ads.

### Which is updated more often, CASSY App or phyphox?

CASSY App ships an update every 3 months, and phyphox every 3 months. Most recently, CASSY App was updated on October 24, 2026 and phyphox on October 24, 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.*