# Spool Buddy vs O

The clearest difference is in-app purchases: O at none against Spool Buddy's 3. O also leads on update cadence (every 4 days vs every 2 weeks) and iOS requirement (16.0 vs 18.2). Spool Buddy's advantage is device support (3 vs 1). On price and ads there is nothing between them.

Both are free to download. Spool Buddy sells 3 one-off in-app purchases. O asks for nothing beyond the download.

Spool Buddy ships an update every 2 weeks, O every 4 days. The most recent releases landed on September 24, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Spool Buddy | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.3 (9 ratings)](https://appshunter.io/ios/app/spool-buddy/id6752347588/reviews)** | — |
| Number of ratings | **9** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 8 MB | 57 MB |
| Requires iOS | 18.2 | **16.0** |
| Devices | **iPhone, iPad, Mac** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Martian Code Oy](https://appshunter.io/developer/1099214691) | [PUFin ID A/S](https://appshunter.io/developer/1614643757) |

## What reviewers say

### Spool Buddy

[App page](https://appshunter.io/ios/app/spool-buddy/id6752347588)

Effortlessly manage your 3D printing filament inventory. Track brands, colors, and usage with a simple, fast interface. Syncs seamlessly across Apple devices without requiring logins or network calls.

**Highlights:** iCloud syncing, No logins or network calls, Track brands, colors, and modifiers, Search and filter by properties, Usage and inventory tracking, Optimized for iOS and macOS

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Small Tip | $0.99 | one-time |
| Medium Tip | $2.99 | one-time |
| Large Tip | $4.99 | one-time |


### O

[App page](https://appshunter.io/ios/app/o-key-authenticator/id6776659466)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Spool Buddy free?

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

### Is O free?

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

### Do Spool Buddy or O have ads?

Neither Spool Buddy nor O shows ads.

### Which is updated more often, Spool Buddy or O?

Spool Buddy ships an update every 2 weeks, and O every 4 days. Most recently, Spool Buddy was updated on September 24, 2026 and O on October 10, 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.*