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
Chapters
Chapters can create new ePub documents and open existing ePub files for editing
$8.99 · In-app purchases
PRICE
$8.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 5.0
1 ratings · Top 5%
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 should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
What's included14 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
Preview a sample Build Kit No email needed
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 Chapters: map the core Productivity 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 better categorization and tagging features.
Assumption to check: Users find it difficult to manage multiple notes.
Validate with people who use this workflow before building.
Hypothesis 2
Enhance cloud sync capabilities.
Assumption to check: Syncing issues across devices.
Validate with people who use this workflow before building.
Hypothesis 3
Allow more background colors and fonts.
Assumption to check: Limited customization options for note appearance.
Validate with people who use this workflow before building.
Hypothesis 4
Introduce sharing features for collaborative editing.
Assumption to check: No support for collaboration on notes.
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
Chapters can create new ePub documents and open existing ePub files for editing. ePub is the most widely adopted file format for ebooks. ePub files reflow their content for comfortable reading on screen of any size from smartphones to desktops. Each document's content zipped into a single file for maximum portability. It is an open and vendor-independent file format based on popular web standards, such as HTML and CSS. With Chapters, you can ▪ Open existing files and create new ePub documents ▪ View an entire document in vertical scroll view ▪ Pinch to zoom and smart zoom with double-tap ▪ Edit and format document’s text ▪ Save your changes back to the file ▪ Use Table of Contents to jump ahead (on Mac only at the moment) ▪ Print and export to PDF (on Mac only at the moment) ▪ Add cover image and modify metadata (on Mac only at the moment) Chapters also supports ▪ iCloud Drive for keeping documents in sync on all your devices ▪ Autosaving automatically saves changes in background while you are editing ▪ Unlimited undo and redo as you edit ▪ Browsing previous changes and restoring them ▪ Resume your work right where you left off once app launches ▪ Side by side multitasking with another app in full screen split view on Mac and iPad ▪ Sharing documents with others via Messages, Mail and AirDrop If you encounter a bug or app crashing, please contact app’s support at [email protected] Thank you!
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
TypeScript
Axios
@react-navigation/native
@react-native-async-storage/async-storage
BUILD KIT DIFFICULTY
Intermediate
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.
