Comparison

Parallel Books vs Glassboxx

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

Head to head
About

Parallel Books

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
Read full description

Become fluent in a new language. Read a book in your new tongue while having a parallel copy in your native language handy for reference. Now thanks to Parallel Books, this technique is available on iPad, iPhone and iPod touch. Translations will automatically stay in sync, leaving you free to be immersed in the words on the page. Reading a book in two different languages at the same time has never been easier! - Designed for people learning a new language. - Displays a book simultaneously in two different languages. - Translations stay in sync as you read. - Stretchy, “chewing gum" overlay visually connects parallel content. - Chewing gum overlay can be hidden. - Translations can be displayed in two columns on the screen, or each translation can fill an entire screen. - Continuously scrolls or pages through content without needing to change mode. - Tapping on a paragraph shows the translation of that paragraph. - Double tapping hides tool bars, giving more space. - Multicolored highlights and searchable notes can be added. - Includes day and night themes. - Currently books are available in English, German, French, Spanish, Portuguese, Russian, Italian, Dutch, Swedish, Esperanto, Korean, Chinese, Arabic plus more. - Some books include multiple translations in the same language; ideal for literature and translation students. - Parallel Books is in development for other platforms. - New books are being added all the time. - All books are currently FREE.

About

Glassboxx

Access your purchased eBooks and audiobooks from affiliated stores in one secure app. No passwords needed, just your email and a verification code. Enjoy offline reading and listening with advanced playback and reading features.

Highlights
  • Unified eBook and audiobook library
  • No password login
  • Offline reading and listening
  • Auto-save reading/listening position
  • Customizable reader (font, background)
  • Audio playback controls (sleep timer, skip)
  • Full text search
Features
Read full description

Welcome to Glassboxx: hassle-free eBook and audiobook access, all in one place. Glassboxx cuts through all digital content ‘authentication’ issues, consolidating your eBook AND audiobook purchases made through affiliated stores, within an eminently user-friendly, secure environment. No password required – simply log in with the email address used to buy the book and enter the verification code sent to your email – and your content awaits in the ‘My Books’ area of the app, with formats clearly labelled. With the content in the cloud, downloading requires an initial internet connection, but once downloaded, your books can be enjoyed to your heart’s content in the remotest, furthest-flung corners of the earth, where internet penetration is a mere pipe-dream… THE AUDIO-PLAYER WILL: • Auto-save your current position in the book – so that you can pick up right where you left off, even if listening on different devices • Allow for skip forward/backward to recap where relevant • Offer sleep timer option • Play on lock-screen, enabling easy access to playback controls • Play in background whilst browsing other apps • Play immediately, and download in the background (provided internet access is available) THE EREADER ALLOWS FOR: • Page book-marking, opening the title at the right place when you pick up, even across multiple devices • Font-size and font face changes, as well as dyslexic-friendly font • Background colour changes • Full text search Welcome to the Glassboxx community!

Screenshots

Parallel Books4 screens
Glassboxx4 screens

Verdict

The call

The clearest difference is rating: Parallel Books at 5.0 against Glassboxx's 3.1. Parallel Books also leads on review sentiment (40% vs 28%). Glassboxx's advantage is ratings volume (74 vs 1) and update cadence (every 6 weeks vs every 3 months). On price, ads, in-app purchases and monetization model 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. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Parallel Books holds the better App Store score, 5.0 against 3.1. That said, the two scores are not equally well evidenced: Glassboxx has 74 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 40% of Parallel Books's written reviews are positive against 28% of Glassboxx's.

UpkeepUpdate frequency

Parallel Books ships an update every 3 months, Glassboxx every 6 weeks. The most recent releases landed on October 21, 2026 and October 25, 2026 respectively.

Scorecard4 real differences · 6 level
Parallel Books versus Glassboxx: the parameters behind the verdict, then further details
ParameterParallel BooksGlassboxx
PriceFreeFree
Rating5.0 (1 ratings) — better3.1 (74 ratings)
Positive reviews40.0% of reviews — better27.8% of reviews
Number of ratings174 — better
Update frequencyEvery 3 monthsEvery 6 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.6 — better16.0
Further details — not scored
Size2 MB35 MB
Age rating12+12+
DeveloperHigh Tea IT LimitedGlassboxx Limited

Customer experience

Parallel Books

All ratings77 ratings
Positive75.3%
Neutral0.0%
Negative24.7%
Written reviews30 reviews
Positive40.0%
Neutral3.3%
Negative56.7%

Glassboxx

All ratings74 ratings
Positive51.4%
Neutral4.1%
Negative44.6%
Written reviews97 reviews
Positive27.8%
Neutral4.1%
Negative68.0%

Bugs and requests

Parallel Books

Not enough reviews yet to summarise bugs or requests.

Glassboxx

Reported bugs

36 issues
  • App crashes on startup
  • App crashes when loading downloaded book
  • App crashes between chapters
  • App freezes
  • App won't open
Show 31 more
  • App shows blank pages
  • App does not rotate
  • App shuts itself off
  • App is slow
  • App has huge margins
  • App has no landscape mode
  • App has no annotation
  • App has no dictionary
  • App has unresponsive buttons
  • App freezes regularly
  • App cannot flick through chapters
  • App touch response is slow
  • App target areas are small
  • App opens to empty screen
  • App settings cannot be closed
  • App has only one font
  • App text is too faint
  • App has visibility/alignment/color jankiness
  • Playback speed resets to 1x when app is minimized
  • Verification codes not sent or expired
  • Books not downloading
  • Purchased books not displaying
  • Login issues
  • Table of contents unresponsive
  • Cannot zoom
  • Cannot navigate easily
  • Screen color resets
  • App not working on iPad
  • Download issues
  • App is unusable
  • Progress bar cannot disappear

Requested features

8 requests
  • Bookmark feature
  • See time remaining in entire audiobook
  • Pagination via cursor keys on iPad Magic Keyboard
  • Dark mode option
  • Advanced analytics dashboard
Show 3 more
  • More titles available
  • Ability to highlight and look up words
  • More standard format (e.g., PDF)

In-app purchases

None

Parallel Books

No in-app purchases

None

Glassboxx

No in-app purchases

Questions

Is Parallel Books free?
Parallel Books is free to download, with no in-app purchases.
Is Glassboxx free?
Glassboxx is free to download, with no in-app purchases.
Which has better reviews, Parallel Books or Glassboxx?
Parallel Books is rated higher. Parallel Books averages 5.0 out of 5 from 1 ratings, while Glassboxx averages 3.1 from 74 ratings.
Do Parallel Books or Glassboxx have ads?
Neither Parallel Books nor Glassboxx shows ads.
Which is updated more often, Parallel Books or Glassboxx?
Parallel Books ships an update every 3 months, and Glassboxx every 6 weeks. Most recently, Parallel Books was updated on October 21, 2026 and Glassboxx on October 25, 2026.

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