# Parallel Books vs InDelve

The clearest difference is in-app purchases: Parallel Books at none against InDelve's 3. Parallel Books also leads on update cadence (every 3 months vs every 8 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. InDelve sells 3 in-app purchases, starting at $2.99 per month. Parallel Books asks for nothing beyond the download.

Parallel Books ships an update every 3 months, InDelve every 8 months. The most recent releases landed on October 17, 2026 and September 25, 2026 respectively.

## The numbers

| Metric | Parallel Books | InDelve |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 40.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 8 months |
| Monetization | Free | — |
| Size | 2 MB | 29 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 12+ | 4+ |
| Developer | [High Tea IT Limited](https://appshunter.io/developer/1045596663) | [Mark Edmunds](https://appshunter.io/developer/946389648) |

## What reviewers say

### Parallel Books

[App page](https://appshunter.io/ios/app/parallel-books/id1045596664)

Learn a new language by reading books with side-by-side translations. This app keeps translations synchronized as you read, allowing for full immersion. Easily switch between display modes and add notes for a personalized learning experience.

**Highlights:** Dual language display, Synchronized translations, Adjustable display modes, Searchable notes, Day/night themes, Highlighting

**Features:** macOS Compatibility

**In-app purchases:** none


### InDelve

[App page](https://appshunter.io/ios/app/indelve-deep-reading/id6754034626)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $2.99 | per month |
| Annual | $29.99 | per year |
| Lifetime | $9.99 | one-time |


## Frequently asked questions

### Is Parallel Books free?

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

### Is InDelve free?

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

### Do Parallel Books or InDelve have ads?

Neither Parallel Books nor InDelve shows ads.

### Which is updated more often, Parallel Books or InDelve?

Parallel Books ships an update every 3 months, and InDelve every 8 months. Most recently, Parallel Books was updated on October 17, 2026 and InDelve on September 25, 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.*