Comparison

KO Reader vs Parallèle Reader

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

Head to head
About

KO Reader

This app transforms web articles, ebooks, and PDFs into natural-sounding speech using on-device AI. Enjoy private, offline listening with customizable voices and playback speeds. Export audio for later or read anywhere without an internet connection.

Highlights
  • On-device text-to-speech
  • Supports web articles, EPUB, PDF, and plain text
  • 53 neural voices in 9 languages
  • Customizable playback speed
  • Audio export to m4a/m4b
  • Offline functionality
  • Privacy-focused, no tracking
Currently charting
Read full description

KO Reader turns web articles, ebooks, and PDFs into natural-sounding speech — entirely on your device. No cloud, no tracking, no subscriptions. Paste a URL or open an EPUB or PDF, and KO Reader reads it aloud with a neural AI voice. Everything runs locally, so your reading stays private and works anywhere — on the train, on a plane, or off-grid. Export your favorite articles or books to m4a or m4b files. WHAT YOU CAN READ • Web articles — Wikipedia, news sites, blogs, and Substack • Fanfiction — Archive of Our Own, Royal Road, and Wattpad, with chapter detection • EPUB ebooks with full chapter navigation • PDF documents • Plain text — paste or type any content • Safari Share Extension — send articles to KO Reader with one tap NATURAL AI VOICES • 53 neural voices across 9 languages: American and British English, Spanish, French, Italian, Portuguese, Japanese, Mandarin, and Hindi • Preview any voice before selecting it • Mark favorites for quick access • Playback speed from 0.5x to 2.0x • Smart heteronym resolution — the voice knows the difference between "lead" (the metal) and "lead" (to guide), "wound" (injury) and "wound" (past of wind) • Custom pronunciation dictionary — teach the reader how to say names, jargon, or anything you like READ YOUR WAY • Reading queue — line up multiple articles and auto-advance • Bookmarks — save passages to come back to • Reading history — pick up where you left off, across books and articles • Chapter pre-generation — book chapters start instantly, no waiting between them • Audio export — save generated audio for offline listening • Adjustable article font (system, serif, monospaced, rounded) and Dynamic Type support BUILT FOR ACCESSIBILITY • Full VoiceOver support with labeled controls throughout • Haptic feedback on transport controls and sleep timer • Background audio — listen while you use other apps or with the screen off • Sleep timer — stops playback when you drift off • Works with AirPods, Bluetooth speakers, and CarPlay RUNS EVERYWHERE • Universal app for iPhone, iPad, and Mac • macOS keyboard shortcuts (Space to play/pause, Cmd+← and Cmd+→ to skip) • Optimized for Apple Silicon with optional CoreML acceleration • Adjustable CPU thread count for performance tuning PRIVACY FIRST • 100% on-device TTS — your content never leaves your phone • No accounts, no analytics, no tracking, no ads • No internet required after the one-time model download • Reading progress stored locally only KO Reader downloads a ~350 MB neural voice model on first launch. After that, everything works fully offline. Powered by the open-source Kokoro TTS model (Apache 2.0).

About

Parallèle Reader

Read full description

Read the books you love - and, whenever you like, read them in two languages, side by side. Parallèle Reader is a calm, aesthetic everyday reader for your books. It also has a language companion built in: open a book in its original language and a clean translation appears right beside it - there when you need it, out of the way when you don't. FEATURES - Read your own EPUB, PDF, and text files (five timeless classics included free, in their original languages) - Side-by-side bilingual reading in split screen — original and translation, page by page - Translate offline with Apple's on-device engine — no internet needed once your languages are downloaded, or connect your own DeepL key - Hide the translation and reveal it with a tap to test yourself - Long-press any word or passage to look it up, highlight it, add a note, or save it - A personal vocabulary that builds as you read — export it as a TSV file - Highlight in five colors, add notes, and bookmark pages — all organized by book - Reading stats with a heatmap that turns your daily progress into a streak — minutes read, books finished, and more - iCloud sync keeps your reading position, highlights, and vocabulary together across iPhone and iPad - Collections and smart shelves for Favorites and Finished, plus search by title, author, or language - Four reading themes (Warm Paper, Sepia, Light, Dark) - Classic serif fonts, adjustable size, spacing, and margins, and a focus mode WHO IT'S FOR You just love reading — a distraction-free reader for your own library, with stats that make the habit stick. Language learners — read authentic books instead of exercises; reading in context teaches what flashcards can't. Heritage and bilingual readers — move freely between both your languages on every page. Anyone after a book that was never translated for sale — read the original with a translation alongside. HOW IT WORKS Open one of the included classics, or import your own EPUB, PDF, or text file. In split screen, the original and a clean translation appear side by side, page by page — on your device with Apple Translate, or through your own DeepL key. Long-press a word or passage to look it up, highlight it, add a note, or save it to your vocabulary. Prefer to test yourself? Hide the translation and reveal it with a tap. PRICING Try Parallèle Reader free for 7 days. After the trial, a single one-time purchase unlocks the full app. PRIVACY Your reading stays private. iCloud sync is optional and connects only your own devices through your Apple ID — your reading habits never reach our servers. Translate entirely on-device with Apple Translate, and if you add a DeepL key, it's stored securely on your device. Whether you're rereading an old favorite or finally reading that novel in its original language, Parallèle Reader makes reading feel good — and quietly makes you better at it.

Screenshots

KO Reader4 screens
Parallèle Reader4 screens

Verdict

The call

The clearest difference is price: Parallèle Reader at Free against KO Reader's $3.99. KO Reader's advantage is in-app purchases (none vs 1) and chart position (#5 vs unranked). On ads, device support and iOS requirement 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

Parallèle Reader is free to download; KO Reader costs $3.99 up front. Parallèle Reader sells 1 one-off in-app purchase. KO Reader asks for nothing beyond the download.

Scorecard3 real differences · 8 level
KO Reader versus Parallèle Reader: the parameters behind the verdict, then further details
ParameterKO ReaderParallèle Reader
Price$3.99Free — better
Rating3.7 (3 ratings) — better—
Positive reviews66.7% of reviews—
Number of ratings3 — better—
Update frequency—Every 3 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaid—
Best chart rank#5 — better—
DevicesiPhone, iPad, Mac — betteriPhone, iPad
Requires iOS18.618.6
Further details — not scored
Size26 MB14 MB
Age rating4+4+
DeveloperJames Carrell IITemirlan Abdyldaev

In-app purchases

None

KO Reader

No in-app purchases

1 purchases

Parallèle Reader

One-time1
  • Unlock Parallèle Reader$9.99

Questions

Is KO Reader free?
KO Reader costs $3.99, with no in-app purchases.
Is Parallèle Reader free?
Parallèle Reader is free to download, with in-app purchases available.
Do KO Reader or Parallèle Reader have ads?
Neither KO Reader nor Parallèle Reader shows ads.

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