# PPAS eReader vs Stacks

The clearest difference is in-app purchases: PPAS eReader at none against Stacks's 4. PPAS eReader also leads on iOS requirement (15.6 vs 17.0). Stacks's advantage is update cadence (every 6 days vs every 43 months). On price, ads and device support there is nothing between them.

Both are free to download. Stacks sells 4 in-app purchases, starting at $2.99 per month. PPAS eReader asks for nothing beyond the download.

PPAS eReader ships an update every 43 months, Stacks every 6 days. The most recent releases landed on October 29, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | PPAS eReader | Stacks |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/stacks-book-scanner-and-library/id6778984902/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 43 months | **Every 6 days** |
| Monetization | — | Freemium |
| Size | 46 MB | 15 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Xentral Methods](https://appshunter.io/developer/464707106) | [Zenmonkeys Digital LLC](https://appshunter.io/developer/1868802546) |

## What reviewers say

### PPAS eReader

[App page](https://appshunter.io/ios/app/ppas-ereader/id768470382)

**Features:** macOS Compatibility

**In-app purchases:** none


### Stacks

[App page](https://appshunter.io/ios/app/stacks-book-scanner-and-library/id6778984902)

Digitally catalog your physical book collection by simply photographing your shelves. The app automatically identifies titles, authors, and covers, then organizes your library with smart sorting and insightful analytics. Never forget if you own a book or who borrowed it again.

**Highlights:** Scan entire bookshelves with one photo, Automatic book identification (title, author, cover), Visual library display with spine width and color, Smart sorting by author, genre, or color, Track lent books and borrower information, Personalized reading recommendations based on owned books, AI-powered book concierge for recommendations and discussions

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Monthly | $2.99 | per month |
| Pro Yearly | $19.99 | per year |
| 3 Scans | $0.99 | one-time |
| 15 Scans | $3.99 | one-time |


## Frequently asked questions

### Is PPAS eReader free?

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

### Is Stacks free?

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

### Do PPAS eReader or Stacks have ads?

Neither PPAS eReader nor Stacks shows ads.

### Which is updated more often, PPAS eReader or Stacks?

PPAS eReader ships an update every 43 months, and Stacks every 6 days. Most recently, PPAS eReader was updated on October 29, 2026 and Stacks on October 25, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*