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.
App Overview
Google Play Books & Audiobooks
All the books you love
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.4
9,643 ratings · Top 30%
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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What's included18 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.
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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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Google Play Books & Audiobooks: 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
Offer a larger selection of free books and audiobooks.
Assumption to check: Limited free content available.
Validate with people who use this workflow before building.
Hypothesis 2
Implement a guided onboarding experience.
Assumption to check: Difficult navigation for new users.
Validate with people who use this workflow before building.
Hypothesis 3
Provide clearer explanations of subscription tiers and benefits.
Assumption to check: Subscription pricing can be confusing.
Validate with people who use this workflow before building.
Hypothesis 4
Optimize app performance for better handling of extensive user libraries.
Assumption to check: Performance issues with large libraries.
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
All the books you love. On the page or out loud. Anywhere you are. Dive into a world of stories with Google Play Books! Explore millions of ebooks, audiobooks, comics, and manga — all in one app. Key Features: • Your library, anywhere: Enjoy books on your phone, tablet, computer, or even in your car with CarPlay. Plus, you can download books to read offline. • Organize with shelves: Personalize your digital library with custom shelves to categorize your books by genre, author, or any theme you’d like. • Audio immersion: Enjoy a vast library of audiobooks with customizable playback speed, sleep timers, and bookmarking to enhance your listening experience. • Smart notes: Jot down notes while you read that sync with your Google Drive and can be shared for easy collaboration. • Kid–friendly reading tools: Let kids explore word definitions or listen to books aloud. Note: Reading tools are available in English only. • Immersive comics: Experience Bubble Zoom for a specialized comic and manga reading experience. • Hands–free reading: Control your audiobook with your voice using Siri. • Read your way: Customize your reading experience by adjusting the font, text size, brightness, and more. Millions of stories await on Google Play Books! Download now and start reading.
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
Zustand
Axios
React Navigation
expo-av
BUILD KIT DIFFICULTY
Expert
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.
