Comparison

OneBook vs DejaVocab

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

Head to head
About

OneBook

This app offers a comprehensive language learning experience by integrating audiobooks, podcasts, and videos. It features AI-powered tools for instant text explanations, word lookup, and subtitle generation, supporting over 60 languages.

Highlights
  • AI Instant Tutor for text explanations
  • Automatic subtitle generation for audiobooks
  • Real-person narration for eBooks
  • Interactive PDF audio books
  • Efficient word and sentence lookup
  • Vocabulary level highlighting
  • Multiple reading modes
Features
Read full description

OneBook is a multilingual learning hub for shadowing audiobooks, podcasts, and videos—with AI context lookup while you read and listen. Core Features 【Audiobook Deep Learning】 【Exclusive Subtitle Generation】: First to support auto-generating synchronized subtitles for m4b/Audible audiobooks. Millions of Audible titles become readable and learnable. 【Real-Person Narration for eBooks】: Supports epub3 books narrated by real people (not synthetic TTS), enabling synchronized listening and reading. 【Interactive PDF Audio Books】: Tap on text within PDF picture books to play the corresponding audio, creating an interactive read-along experience. 【Intelligent Reading & Lookup】 【Efficient Word & Sentence Lookup】: Tap to look up a word, long-press to look up a sentence. Incorporates a feature similar to Kindle's Word Wise, significantly reducing lookup effort. 【AI Instant Tutor】: Select any text for instant AI explanations on grammar, context, sentence structure, and more—like having a personal teacher on hand. 【Vocabulary Level Highlighting】: Words are automatically color-coded based on difficulty, making key terms stand out at a glance. 【Multi-Mode Immersive Experience】 【Multiple Reading Modes】: Includes ADHD Bionic Reading, Cinematically-Scrolling, Immersive Focus Mode, Background Music Reading, Shadowing Practice, and more to suit different scenarios. 【Whisper-Style Audiobook】: Supports offline listening with optional ambient white noise, crafting a comfortable and focused listening experience. 【All-Platform Resource Integration】 Learn directly from videos and audio on platforms like YouTube, Bilibili, and Apple Podcasts. Supports OPDS catalogs for easy subscription to news, foreign periodicals, and magazines. Import personal resources via WebDAV or cloud storage, with real-time synchronization across multiple devices. 【Multilingual & Customizable】 Supports learning for 60+ global languages, including German, French, Italian, Spanish, and other less-commonly-taught languages. Compatible with importing any MDX dictionary file, allowing you to use your preferred word references. Supports custom AI models to tailor the Q&A experience to your needs. Learning Management & Statistics Pre-study new words before reading, with automatic tracking during your session. Detailed reading statistics and insights to help you track progress and outcomes. Why Choose Us? All in One: A single app integrates audiobooks, reading, video learning, vocabulary management, AI Q&A, and resource syncing. Constantly Evolving: Continuously updated with new features and improvements, with more exciting additions on the way. Welcome to Download and Experience Begin your efficient, immersive, and personalized language learning and reading journey today. Privacy Policy: https://www.onebook2025.top/privacy/ Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

DejaVocab

This app helps you learn languages by immersing you in real-world content like videos, podcasts, and books. It builds a personal language corpus by capturing and organizing language chunks from natural input, allowing you to review words within their original context. The system integrates spoken and written language for a continuous learning experience.

Highlights
  • Learn from videos, podcasts, and audiobooks
  • Build a personal language corpus
  • Review vocabulary in original context
  • Integrates spoken and written language
  • Supports EPUB, PDF, and text files
Features
Read full description

Deja 从一个问题开始: 语言,为什么总是被学成抽象的单词? 在真实世界中,语言来自视频、播客、阅读和声音。 Deja 将这些语境中的表达自动提取、组织,逐渐形成一个属于自己的语料系统。 复习不再是孤立的记忆,而是回到语言第一次出现的那个语境。 阅读、听力、学习不再分离,所有输入汇聚成一条连续的语言路径。 Deja 不属于某一种格式或平台,它试图构建的,是一个会随着使用不断生长的语言系统。 Deja starts with a simple idea: Language is not learned from isolated words, but from real usage. Import videos, podcasts, books, or any text. Deja automatically captures phrases in context and turns scattered exposure into a growing personal corpus. Review is not repetition. It is a return to the moment where the language first made sense. Reading, listening, and studying are no longer separated. Everything flows into one continuous system, one evolving memory. Deja is not about formats or platforms. It is about building a language system that grows with you. Contact WeChat: longhao1596 Discord Community: https://discord.gg/AC7sNMJW Privacy Policy: https://dejavocab.com/privacy-policy/ Subscription Information Subscriptions renew automatically 24 hours before the end of the current period You can manage or cancel your subscription in Apple ID settings at any time After cancellation, access remains until the end of the current subscription period Payment will be charged to your iTunes account upon confirmation of purchase Terms of Service: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Don’t let words slip past unnoticed. Let DejaVocab capture every meaningful chunk of language. Download DejaVocab and build your own language corpus.

Screenshots

OneBook4 screens
DejaVocab4 screens

Verdict

The call

The clearest difference is rating: OneBook at 5.0 against DejaVocab's 4.6. OneBook also leads on review sentiment (97% vs 87%) and iOS requirement (15.0 vs 17.6). On price, ratings volume, update cadence and ads 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. OneBook sells 2 in-app purchases, starting at $8.00 per month and DejaVocab sells 6 in-app purchases, starting at $5.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

OneBook holds the better App Store score, 5.0 against 4.6. Both are backed by a comparable volume of ratings — 64 and 64 respectively. Written reviews point the same way: 97% of OneBook's written reviews are positive against 87% of DejaVocab's.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly weekly. Both last shipped on November 5, 2026.

Scorecard3 real differences · 7 level
OneBook versus DejaVocab: the parameters behind the verdict, then further details
ParameterOneBookDejaVocab
PriceFreeFree
Rating5.0 (64 ratings) — better4.6 (64 ratings)
Positive reviews97.3% of reviews — better86.6% of reviews
Number of ratings6464
Update frequencyWeeklyWeekly
AdsNoNo
In-app purchasesYesYes
MonetizationFreemiumFreemium
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better17.6
Further details — not scored
Size224 MB360 MB
Age rating4+17+
Developer翊 林灏 龙

Customer experience

OneBook

All ratings64 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews37 reviews
Positive97.3%
Neutral2.7%
Negative0.0%

DejaVocab

All ratings59 ratings
Positive86.4%
Neutral1.7%
Negative11.9%
Written reviews67 reviews
Positive86.6%
Neutral4.5%
Negative9.0%

In-app purchases

2 purchases

OneBook

Subscriptions1
  • OneBook Premium Monthly$8.001 Month
One-time1
  • AI Pack 1000$5.00
6 purchases

DejaVocab

Subscriptions4
  • DejaVocab 高级版3 Days trial$5.991 Month
  • DejaVocab 高级版3 Days trial$7.991 Month
  • DejaVocab 高级版年付7 Days trial$49.991 Year
Show 1 more
  • DejaVocab 专业版年付7 Days trial$69.991 Year
One-time2
  • DejaVocab 共建者$199.99
  • DejaVocab 共建者 Plus$299.99

Questions

Is OneBook free?
OneBook is free to download, with in-app purchases available.
Is DejaVocab free?
DejaVocab is free to download, with in-app purchases available.
Which has better reviews, OneBook or DejaVocab?
OneBook is rated higher. OneBook averages 5.0 out of 5 from 64 ratings, while DejaVocab averages 4.6 from 64 ratings.
Do OneBook or DejaVocab have ads?
Neither OneBook nor DejaVocab shows ads.
Which is updated more often, OneBook or DejaVocab?
OneBook ships an update weekly, and DejaVocab weekly. Most recently, OneBook was updated on November 5, 2026 and DejaVocab on November 5, 2026.

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