# InkShelf vs Spine

The clearest difference is in-app purchases: Spine at none against InkShelf's 2. Spine also leads on update cadence (every 4 days vs monthly). InkShelf's advantage is iOS requirement (13.0 vs 26.0). On price, ads and device support there is nothing between them.

Both are free to download. InkShelf sells 2 in-app purchases, starting at $4.99 per month. Spine asks for nothing beyond the download.

InkShelf ships an update monthly, Spine every 4 days. The most recent releases landed on October 4, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | InkShelf | Spine |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.8 (25 ratings)](https://appshunter.io/ios/app/spine-audiobook-player/id6764636615/reviews)** |
| Number of ratings | — | **25** |
| Positive reviews | — | 81.8% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Monthly | **Every 4 days** |
| Monetization | — | Free |
| Size | 38 MB | 15 MB |
| Requires iOS | **13.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, Apple Watch |
| Age rating | 4+ | 12+ |
| Developer | [Yoshinn CO., LTD.](https://appshunter.io/developer/1856072122) | [Accelyze Inc.](https://appshunter.io/developer/1895859588) |

## What reviewers say

### InkShelf

[App page](https://appshunter.io/ios/app/inkshelf/id6755747348)

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Inkshelf Pro Monthly | $4.99 | per month |
| Inkshelf Pro Yearly | $49.99 | per year |


### Spine

[App page](https://appshunter.io/ios/app/spine-audiobook-player/id6764636615)

This app enhances audiobook listening with features like listener levels, daily streaks, and shareable year-end recaps. It offers a beautiful, integrated player and syncs with Hardcover, all while keeping your data private on-device.

**Highlights:** Integrated audiobook player, Listener levels and daily streaks, Hardcover sync, On-device AI summaries, Shareable year-in-review recap, Lock screen and widget controls

**Features:** macOS Compatibility, Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is InkShelf free?

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

### Is Spine free?

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

### Do InkShelf or Spine have ads?

Neither InkShelf nor Spine shows ads.

### Which is updated more often, InkShelf or Spine?

InkShelf ships an update monthly, and Spine every 4 days. Most recently, InkShelf was updated on October 4, 2026 and Spine on October 20, 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.*