# BookLight vs KeyReader

The clearest difference is update cadence: BookLight at every 4 days against KeyReader's every 3 weeks. BookLight also leads on iOS requirement (16.4 vs 18.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. BookLight sells 3 in-app purchases, starting at $0.99 per month and KeyReader sells 3 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

BookLight ships an update every 4 days, KeyReader every 3 weeks. The most recent releases landed on October 31, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | BookLight | KeyReader |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 4 days** | Every 3 weeks |
| Monetization | Free with in-app purchases | — |
| Size | 94 MB | 7 MB |
| Requires iOS | **16.4** | 18.0 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Jungjun Lee](https://appshunter.io/developer/1485806455) | [Oleg Strigunov](https://appshunter.io/developer/1705947979) |

## What reviewers say

### BookLight

[App page](https://appshunter.io/ios/app/booklight-epub-translator/id6759386987)

This app helps language learners build vocabulary by translating words with a single tap while reading EPUB, PDF, or TXT files. It automatically saves new words and uses spaced repetition flashcards to aid memorization, eliminating the need for manual flashcard creation or app switching.

**Highlights:** Tap to translate words instantly, Automatic vocabulary saving, Spaced-repetition flashcards, Import EPUB, PDF, TXT files, Offline reading support, Customizable reading themes and fonts, Pronunciation audio

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Plan | $0.99 | per month |
| Yearly Plan | $7.99 | per year |
| Lifetime Plan | $9.99 | one-time |


### KeyReader

[App page](https://appshunter.io/ios/app/keyreader/id6762510058)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlimited Reading | $2.99 | per month |
| Unlimited Reading | $19.99 | per year |
| Unlimited Reading | $49.99 | one-time |


## Frequently asked questions

### Is BookLight free?

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

### Is KeyReader free?

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

### Do BookLight or KeyReader have ads?

Neither BookLight nor KeyReader shows ads.

### Which is updated more often, BookLight or KeyReader?

BookLight ships an update every 4 days, and KeyReader every 3 weeks. Most recently, BookLight was updated on October 31, 2026 and KeyReader on October 7, 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.*