# BTLB vs Parallel Books

The clearest difference is update cadence: BTLB at monthly against Parallel Books's every 3 months. Parallel Books's advantage is iOS requirement (15.6 vs 17.2). 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.

BTLB ships an update monthly, Parallel Books every 3 months. The most recent releases landed on September 9, 2026 and August 28, 2026 respectively.

## The numbers

| Metric | BTLB | Parallel Books |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 40.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Monthly** | Every 3 months |
| Monetization | — | Free |
| Size | 20 MB | 2 MB |
| Requires iOS | 17.2 | **15.6** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [Martin Kim Đưng-Phạm](https://appshunter.io/developer/383008921) | [High Tea IT Limited](https://appshunter.io/developer/1045596663) |

## What reviewers say

### BTLB

[App page](https://appshunter.io/ios/app/btlb/id383008918)

**Features:** macOS Compatibility

**In-app purchases:** none


### 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


## Frequently asked questions

### Is BTLB free?

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

### Is Parallel Books free?

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

### Do BTLB or Parallel Books have ads?

Neither BTLB nor Parallel Books shows ads.

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

BTLB ships an update monthly, and Parallel Books every 3 months. Most recently, BTLB was updated on September 9, 2026 and Parallel Books on August 28, 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.*