App Overview

KO Reader icon

KO Reader

James Carrell II · Books

KO Reader turns web articles, ebooks, and PDFs into natural-sounding speech — entirely on your device

$3.99 · In-app purchases

PRICE
$3.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
3.7
3 ratings · Top 50%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

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Combine features and design from your favorite apps.

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What's included19 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for KO Reader: map the core Books workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Implement advanced sorting and filtering options.

Assumption to check: Limited book organization features

Validate with people who use this workflow before building.

Hypothesis 2

Add offline access for downloaded books.

Assumption to check: No offline reading capability

Validate with people who use this workflow before building.

Hypothesis 3

Introduce more flexible subscription plans.

Assumption to check: Subscription options are not flexible

Validate with people who use this workflow before building.

Hypothesis 4

Simplify navigation and improve layout for better usability.

Assumption to check: User interface can be cluttered

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store 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).

Written user reviews are not shown here. Check current App Store reviews >

Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
React Native
Expo
Supabase
react-navigation
react-native-paper
zustand
BUILD KIT DIFFICULTY
Advanced

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.