Comparison

Kotobee Reader vs duoBooks

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Kotobee Reader

This app provides an ad-free digital reading experience for interactive ebooks. It supports EPUB 3.0, offers note-taking, highlighting, bookmarking, and text-to-speech functionalities. Access a free digital library for offline reading.

Highlights
  • EPUB 3.0 support
  • Note-taking and highlighting
  • Bookmarking
  • Aggregate annotations to PDF
  • Offline reading
  • Text-to-speech
  • Google lookup
Features
Read full description

Kotobee Reader: Your ultimate interactive ebook reader and ad-free digital reading companion Kotobee Reader is optimized for the EPUB 3.0 standard, supporting interactivity and multiple languages. Access Kotobee Books; a free digital library where you can download classics and ebooks distributed by other users and read offline. Kotobee Reader offers a powerful set of tools to enhance your reading experience: - Note-taking: Add notes to words and paragraphs, and access them later. - Highlighting: Mark important sentences with different color highlights. - Bookmarking: Bookmark multiple pages at different locations - Aggregate annotations: Aggregate your notes, highlights, and bookmarks, into a PDF. - Search: Search inside the chapter or the entire book. - Multiple languages: Use one of more than 16 different languages - Copy to clipboard: Copy any text to your clipboard, to use in external programs. - Text-to-speech: Let the reader speak out any text you choose - Google lookup: Search definitions and explanations directly with a click. Kotobee Reader is perfect for students, educators, and anyone looking for a customizable ebook reading experience. And the best part? No Ads! Read without interruptions. Kotobee Reader ensures an ad-free environment, and we don’t burden you with internal purchases either. For information about Kotobee Reader, please visit https://www.kotobee.com/products/reader For the creation of ebooks using our free software Kotobee Author, please visit https://www.kotobee.com/products/author Kotobee Reader and Kotobee Author are both part of the Kotobee platform: https://www.kotobee.com

About

duoBooks

Read any book in any language with instant translation and detailed word explanations. Build your vocabulary with a personal dictionary and spaced repetition tools. Improve pronunciation with audio voiceovers and master new languages through immersive bilingual reading.

Highlights
  • Instant translation of any book
  • Personalized vocabulary dictionary
  • Spaced repetition for memorization
  • Audio voiceovers for pronunciation
  • Bilingual parallel text reading
  • EPUB reader for custom files
Features
Read full description

Read any book in any language with instant translation into your native language. We offer short stories designed specifically for beginner language learners. Alternatively, you can add any book from your device and read with translation whatever you want. Break any sentence into clear pieces and see every word explained in context. Instantly understand how the sentence works, what each word means, and how it fits into the full translation. In our app, you will also have your personal dictionary where you can keep your vocabulary in one place and easily review it whenever you want. Mastering correct pronunciation is key to language acquisition. In our app, you can listen to audio voiceovers of every sentence or word to hear it pronounced accurately. Immerse yourself in language learning with ease. To learn words, we provide a Spaced Repetition tool. With it you can review words at increasing intervals, ensuring long-term retention and mastery. Swipe through word flashcards effortlessly to build a robust vocabulary and make memorizing words a seamless part of your daily routine. Build your English vocabulary. Many people who are not native English speakers use our app as epub reader to read scientific materials or programming books in English. As long as you have an EPUB file for what you want to read, our app is the best choice. Our bilingual book reader is designed to enhance your language proficiency one page at a time. Practice and study foreign languages by reading parallel texts where every sentence is translated into your native language. Reading books with translation is a proven method for language learners to improve their reading comprehension, expand their vocabulary, and gain a deeper understanding of grammar structures. Read with translation any EPUB ebook from your device, or choose from our library with 3000+ books and short stories. Reading enhances your creativity, imagination, and empathy. Moreover, reading has been shown to reduce stress, improve mental health, and increase our overall well-being. Dive into a world of dual-language storytelling. Don't just take our word for it - hear what our users have to say: "This app has revolutionized my language study! I use it with my own EPUB files in a language I am studying. The interface is intuitive. It's also very fast to use and provides a smooth experience during long reading sessions." Read in English, German, French, Spanish, Italian, or any other language, build your vocabulary, and improve your grammar skills. With our cross-language ebook reader, translate books on the fly and listen to voiceovers of any sentence or word in your book. Best bilingual reading app available. With duoBooks you will: - Take control of your language learning journey and achieve your goals faster and easier than ever before. - Improve speaking by listening to how words and phrases are pronounced correctly. - Easily incorporate reading into your daily routine and reap the numerous benefits of this powerful skill, all while you learn English (or other languages). - Read English books with translation (or Spanish, French, etc.) easily even if it's not your native language. - Study words with scientifically proven technique (Spaced repetition). Swipe word cards and enjoy the process. Smart Interval system is as effective for memorizing words as English lessons. duoBooks offers short stories specifically created for beginners. They use simple vocabulary, repetitive words, simple dialogues, and uncomplicated sentences. Alternatively, we have a vast selection of classic literature. From the works of Edgar Allan Poe to the novels of Jane Austen. With over 3000+ classic ebooks available and the ability to import your own files, you'll never run out of options to practice your language skills. Whether you're a beginner or an advanced learner, duoBooks is your app for language learning success. Start your journey today with our free language learning app!

Screenshots

Kotobee Reader4 screens
duoBooks4 screens

Verdict

The call

The clearest difference is rating: duoBooks at 4.7 against Kotobee Reader's 3.6. duoBooks also leads on update cadence (every 2 weeks vs every 2 months) and review sentiment (69% vs 50%). Kotobee Reader's advantage is in-app purchases (none vs 11) and iOS requirement (13.0 vs 15.0). On price, ratings volume, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. duoBooks sells 11 in-app purchases, starting at $2.99 per month. Kotobee Reader asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

duoBooks holds the better App Store score, 4.7 against 3.6. Both are backed by a comparable volume of ratings — 22 and 48 respectively. Written reviews point the same way: 50% of Kotobee Reader's written reviews are positive against 69% of duoBooks's.

UpkeepUpdate frequency

Kotobee Reader ships an update every 2 months, duoBooks every 2 weeks. The most recent releases landed on September 20, 2026 and September 21, 2026 respectively.

Scorecard6 real differences · 4 level
Kotobee Reader versus duoBooks: the parameters behind the verdict, then further details
ParameterKotobee ReaderduoBooks
PriceFreeFree
Rating3.6 (22 ratings)4.7 (48 ratings) — better
Positive reviews50.0% of reviews68.6% of reviews — better
Number of ratings2248 — better
Update frequencyEvery 2 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13.0 — better15.0
Further details — not scored
Size14 MB54 MB
Age rating4+12+
DeveloperVijuaPlainProg LLC

Customer experience

Kotobee Reader

All ratings22 ratings
Positive63.6%
Neutral4.5%
Negative31.8%
Written reviews16 reviews
Positive50.0%
Neutral12.5%
Negative37.5%

duoBooks

All ratings48 ratings
Positive93.8%
Neutral0.0%
Negative6.3%
Written reviews35 reviews
Positive68.6%
Neutral11.4%
Negative20.0%

In-app purchases

None

Kotobee Reader

No in-app purchases

11 purchases

duoBooks

Subscriptions5
  • Full Plan7 Days trial$2.991 Month
  • Full Plan3 Days trial$6.991 Month
  • Full Plan7 Days trial$17.991 Year
Show 2 more
  • 6 Month Full Plan3 Days trial$19.996 Months
  • Full Yearly Plan3 Days trial$29.991 Year
One-time6
  • War and Peace$0.99
  • Silver Blaze$0.99
  • On The River$0.99
Show 3 more
  • Clochette$0.99
  • The Fishing Hole$0.99
  • Alice in Wonderland$0.99

Questions

Is Kotobee Reader free?
Kotobee Reader is free to download, with no in-app purchases.
Is duoBooks free?
duoBooks is free to download, with in-app purchases available.
Which has better reviews, Kotobee Reader or duoBooks?
duoBooks is rated higher. Kotobee Reader averages 3.6 out of 5 from 22 ratings, while duoBooks averages 4.7 from 48 ratings.
Do Kotobee Reader or duoBooks have ads?
Neither Kotobee Reader nor duoBooks shows ads.
Which is updated more often, Kotobee Reader or duoBooks?
Kotobee Reader ships an update every 2 months, and duoBooks every 2 weeks. Most recently, Kotobee Reader was updated on September 20, 2026 and duoBooks on September 21, 2026.

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