KO Reader vs Parallèle Reader
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- 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
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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).
Parallèle Reader
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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
Verdict
The clearest difference is price: Parallèle Reader at Free against KO Reader's $3.99. Parallèle Reader also leads on rating (5.0 vs 3.6). KO Reader's advantage is in-app purchases (none vs 1) and chart position (#17 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
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.
Parallèle Reader holds the better App Store score, 5.0 against 3.6. That said, the two scores are not equally well evidenced: KO Reader has 5 ratings behind it against 1, so its average is the more settled of the two.
| Parameter | KO Reader | Parallèle Reader |
|---|---|---|
| Price | $3.99 | Free — better |
| Rating | 3.6 (5 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 66.7% of reviews | — |
| Number of ratings | 5 — better | 1 |
| Update frequency | — | Every 3 months |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | — |
| Best chart rank | #17 — better | — |
| Devices | iPhone, iPad, Mac — better | iPhone, iPad |
| Requires iOS | 18.6 | 18.6 |
| Further details — not scored | ||
| Size | 26 MB | 14 MB |
| Age rating | 4+ | 4+ |
| Developer | James Carrell II | Temirlan Abdyldaev |
In-app purchases
KO Reader
No in-app purchases
Parallèle Reader
- Unlock Parallèle Reader$9.99









