# CastleBird vs Alf by Spaceship

The clearest difference is update cadence: Alf by Spaceship at fortnightly against CastleBird's every 3 months. CastleBird's advantage is iOS requirement (15.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

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

CastleBird ships an update every 3 months, Alf by Spaceship fortnightly. The most recent releases landed on September 13, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | CastleBird | Alf by Spaceship |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Fortnightly** |
| Size | 93 MB | 119 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [CastleBird](https://appshunter.io/developer/1689612442) | [Namecheap, Inc](https://appshunter.io/developer/482604035) |

## What reviewers say

### CastleBird

[App page](https://appshunter.io/ios/app/castlebird/id6449547159)

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

**In-app purchases:** none


### Alf by Spaceship

[App page](https://appshunter.io/ios/app/alf-by-spaceship/id6737549639)

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

**In-app purchases:** none


## Frequently asked questions

### Is CastleBird free?

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

### Is Alf by Spaceship free?

Alf by Spaceship is free to download, with no in-app purchases.

### Do CastleBird or Alf by Spaceship have ads?

Neither CastleBird nor Alf by Spaceship shows ads.

### Which is updated more often, CastleBird or Alf by Spaceship?

CastleBird ships an update every 3 months, and Alf by Spaceship fortnightly. Most recently, CastleBird was updated on September 13, 2026 and Alf by Spaceship on September 26, 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.*