# Casty vs Synapse

The clearest difference is iOS requirement: Casty at 15.1 against Synapse's 17. 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 2 days. The most recent releases landed on October 18, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Casty | Synapse |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/casty/id6740439860/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 days | Every 2 days |
| Monetization | Free | — |
| Size | 23 MB | 181 MB |
| Requires iOS | **15.1** | 17 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [Wai Yip Li](https://appshunter.io/developer/1789980681) | [Mattia Capomagi](https://appshunter.io/developer/1895857137) |

## What reviewers say

### Casty

[App page](https://appshunter.io/ios/app/casty/id6740439860)

Transform PDF documents into engaging podcasts with live transcripts and a built-in dictionary. Listen offline to educational content in Japanese or English after generation.

**Highlights:** Convert PDFs to podcasts, Live transcripts, Built-in dictionary, Offline listening, Japanese and English support

**Features:** macOS Compatibility

**In-app purchases:** none


### Synapse

[App page](https://appshunter.io/ios/app/synapse-daily-knowledge/id6764631049)

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

**In-app purchases:** none


## Frequently asked questions

### Is Casty free?

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

### Is Synapse free?

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

### Do Casty or Synapse have ads?

Neither Casty nor Synapse shows ads.

### Which is updated more often, Casty or Synapse?

Casty ships an update every 2 days, and Synapse every 2 days. Most recently, Casty was updated on October 18, 2026 and Synapse on October 13, 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.*