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
NBReader
Experience the ultimate novel-reading app with NB Reader
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 2.7
87 ratings · Below Average
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 NBReader: 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
Focus on curating quality content and partnerships.
Assumption to check: Limited eBook selection compared to competitors
Validate with people who use this workflow before building.
Hypothesis 2
Prioritize performance optimization and user feedback.
Assumption to check: Poor user reviews about app performance
Validate with people who use this workflow before building.
Hypothesis 3
Simplify navigation and improve user onboarding.
Assumption to check: Confusing navigation structure
Validate with people who use this workflow before building.
Hypothesis 4
Introduce features like font size adjustment and theme selection.
Assumption to check: Limited customization options for reading experience
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
Experience the ultimate novel-reading app with NB Reader. Dive into thousands of titles across genres, customize your reading environment, and enjoy advanced features designed for book lovers. Key Features: Immersive Reading Modes: Choose from vertical or horizontal scrolling, adjust font size, line spacing, and margins to suit your preferences. Night & Sepia Modes: Reduce eye strain with easy-to-switch themes for low-light or daytime reading. Automatic Text-to-Speech (TTS): Listen to your favorite novels whenever you’re on the go. Voice playback continues even when the screen is locked. Instant Translation: Translate any paragraph or phrase into English (or your chosen language) with a single tap—no need to leave the app. Offline Library: Download chapters in advance to read without Wi-Fi or cellular data. Perfect for travel, commutes, or areas with limited connectivity. Bookmark & History Management: Save your spot with unlimited bookmarks, organize favorite chapters, and view a complete reading history to jump back in at any time. Earn Free Points Daily: Check in every day to collect spirit stones, redeemable for unlocking premium chapters or themes—no credit card required. Smart Library Organization: Create your own bookshelves, sort by author, genre, or update time, and receive notifications when new chapters are released. Customizable Notifications: Get alerts for daily check-ins, new chapter updates, and special in-app events. Seamless Account Sync: Log in with email or social accounts and sync your library, bookmarks, and reading progress across all your devices. Why NB Reader? NB Reader was built by avid readers and developers who understand what makes a good reading experience. Whether you’re into romance, fantasy, sci-fi, or historical novels, NB Reader delivers smooth performance and a clutter-free interface. Enjoy continuous updates, responsive customer support, and a growing catalog of over 1000 titles. Download NB Reader today and transform the way you read. Your next adventure is just a tap away!
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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
Axios
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Zustand
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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.
