Comparison

Reader AI vs Opa! Bilingual Book Reader

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

Head to head
About

Reader AI

Enhance your reading and language learning experience by importing books and articles. Get AI-powered explanations, translations, and summaries. Listen to narrated text and organize your library with customizable features.

Highlights
  • AI-powered word and sentence explanations
  • In-context translation
  • Text-to-speech narration
  • Import EPUB, TXT, MOBI, AZW3, PDF
  • Website and blog following
  • Customizable reading layout
  • PDF annotation
Features
Read full description

Read books and web articles in their original language, with help when you need it. Reader AI brings reading, language learning and listening together. Import your own books, save articles from a link or the Safari share sheet, or follow websites with Feeds, then read in a layout you can make your own. READ AND UNDERSTAND Look up words in context and ask AI to explain sentences, expressions and passages. Set your native language and level for explanations that fit you. Read books and articles side by side with a translation, or the translation only. Ask about a book, quoting several passages, images or part of a PDF page, follow answers back to the text, or get an AI summary of the book or what you've read so far. LISTEN AND FOLLOW ALONG Narration runs on your device after you download a voice pack. Follow the highlighted text, change voices, turn on translated subtitles, and switch between the reader and player without losing your place. PDFs with selectable text can be narrated too. With Pro, Daily Podcast turns new articles from your feeds into an episode each day. BUILD YOUR LIBRARY Import EPUB, TXT, MOBI, AZW3, PDF and other formats. Follow websites and blogs with Feeds. Import from your WebDAV library or OPDS catalogs. Dropbox, OneDrive, Box, Google Drive imports and the Discover catalog are available outside mainland China. Add books to Want to Read and organize articles into folders. MAKE READING YOUR OWN Adjust fonts, spacing and colors, choose a page-turning effect, and use an external keyboard. On iPad, read in separate windows with a sidebar for contents, search and thumbnails. Highlight passages and add notes. Write on PDFs with Apple Pencil or your finger, using pens, highlighter, shapes and a zoom window, then export them. Text on scanned PDF pages is recognized on your device, so you can look up words. REMEMBER WHAT YOU READ Save words, expressions and sentences in Saved with their meanings and original sentences. Review them, track your progress and return to the original passage. FREE READING AND PRO Reading, highlighting, notes and PDF annotation are free. The free bookshelf holds 3 books (articles and the sample book don't count); add a spot for 3 AI credits. The sample book and your first 3 books are free to listen to and translate; other books unlock listening or translation for 5 credits each. A one-time No bookshelf limit purchase or Pro removes the limit and makes every book free to listen to and translate. Free AI credits let you try lookups, explanations and article translation; outside mainland China, you can also watch a short video for credits. Pro includes lookups, explanations, pronunciation, Book Chat, AI Summary, Similar Books and Daily Podcast. Plans and prices are shown in the app. NO APP ACCOUNT REQUIRED Your library, progress and study data are stored on your device and in your iCloud storage. AI features process the requested text and needed context. Narration and book translation run on your device; for Daily Podcast, our server reads your feeds to write each episode. Reward videos outside mainland China are provided by Google AdMob. AI output may contain errors. Only import content you have the right to use. Requires iOS 18 or later. Payment is charged to your Apple Account when you confirm a purchase. Subscriptions renew automatically unless canceled at least 24 hours before the current period ends. Manage or cancel subscriptions in your Apple Account settings and restore purchases in the app. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://reader.lorpaves.com/privacy/ Terms of Service: https://reader.lorpaves.com/terms/

About

Opa! Bilingual Book Reader

Read full description

Elevate literary consumption through our sophisticated dual-text interface. By showcasing source material paired with precise, synchronized equivalents, enthusiasts gain immediate comprehension while maintaining narrative flow. Whenever challenging phrases or intricate syntax appear, clarified explanations hover within your peripheral view. Enhance vocabulary acquisition via tools engineered for fluency improvement. Key Features: - Parallel Presentation: Perfectly synced layouts allow effortless scanning across source paragraphs plus provided interpretations. Frictionless Engagement: Eliminate requirements to jump toward external tools, preserving mental flow. - Precise Segment Mapping: Clean synchronization keeps progress tracking consistent through every chapter. - Minimalist Visual Design: Curated typography, adaptable color themes, plus distraction-free environments maintain concentrated focus upon plot development. - Dynamic Memory Retention: Capture vocabulary items or idiomatic expressions via singular interactions, utilizing spaced repetition cycles for long-term retention. - Comprehensive Format - Compatibility: Import EPUB, MOBI, plus raw TXT files flawlessly. Target Demographics: Academic Students: Perfect for B1-C2 skill levels seeking transitions away from standard primers toward authentic prose. Multilingual Users: Individuals evaluating stylistic nuances plus interpretive subtleties across diverse dialects. Bibliophiles: Anyone wishing to savor global masterpieces using their authentic primary composition. Master complex vocabulary structures effortlessly. Our platform streamlines every aspect concerning prose exploration. Experience stories authentically, gaining mastery over unfamiliar grammar plus unique cultural idioms naturally. Our technical architecture supports massive file libraries, permitting users to organize personal collections effectively. Adjust font sizes, margins, plus background settings to optimize comfort levels during extended sessions. Night mode features assist nocturnal sessions, reducing ocular fatigue significantly. Track personal progress via integrated statistics revealing total time spent plus vocabulary counts acquired. Share highlighted passages directly onto social platforms to discuss literary insights. Receive curated suggestions tailored toward current proficiency levels. Our robust engine handles intricate formatting requirements, ensuring text remains pristine. Whether studying Spanish, German, French, or Japanese, unlock new potential today. Transform mundane practice sessions into delightful adventures. Download now to begin your journey toward total fluency. Access premium features through flexible subscriptions, ensuring continuous updates plus expanded functionality. Your path toward mastering world literature awaits. Explore global classics while refining linguistic skills simultaneously. Everything necessary for success rests within this powerful toolset. Stop feeling stuck; start exploring boundless stories globally. Opa! PREMIUM Get the full experience with Premium month/year subscription plans. Terms and Conditions / Privacy Policy: https://momentarium.app/legal Join our community today.

Screenshots

Reader AI4 screens
Opa! Bilingual Book Reader4 screens

Verdict

The call

The clearest difference is ads: Opa! Bilingual Book Reader at none against Reader AI's shown. On price, update cadence, in-app purchases 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. Reader AI sells 7 in-app purchases, starting at $6.99 per month and Opa! Bilingual Book Reader sells 2 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 5 days. Both last shipped on November 6, 2026.

Scorecard1 real difference · 9 level
Reader AI versus Opa! Bilingual Book Reader: the parameters behind the verdict, then further details
ParameterReader AIOpa! Bilingual Book Reader
PriceFreeFree
Rating2.0 (1 ratings) — better—
Positive reviews0.0% of reviews—
Number of ratings1 — better—
Update frequencyEvery 5 daysEvery 5 days
AdsYesNo — better
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad — betteriPhone
Requires iOS18.017.0 — better
Further details — not scored
Size85 MB3 MB
Age rating12+4+
Developer江 刘Momentarium LLC

In-app purchases

7 purchases

Reader AI

Subscriptions3
  • Monthly$6.991 Month
  • Quarterly$19.993 Months
  • Yearly7 Days trial$69.991 Year
One-time4
  • 100 points$9.99
  • No bookshelf limit$9.99
  • 300 points$29.99
Show 1 more
  • 1000 points$89.99
2 purchases

Opa! Bilingual Book Reader

Subscriptions2
  • Month$4.991 Month
  • Year$14.991 Year

Questions

Is Reader AI free?
Reader AI is free to download, with in-app purchases available.
Is Opa! Bilingual Book Reader free?
Opa! Bilingual Book Reader is free to download, with in-app purchases available.
Do Reader AI or Opa! Bilingual Book Reader have ads?
Reader AI shows ads; Opa! Bilingual Book Reader does not.
Which is updated more often, Reader AI or Opa! Bilingual Book Reader?
Reader AI ships an update every 5 days, and Opa! Bilingual Book Reader every 5 days. Most recently, Reader AI was updated on November 6, 2026 and Opa! Bilingual Book Reader on November 6, 2026.

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