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
CHMate+: EPUB & CHM Reader
CHMate is an amazing way to read eBooks for EPUB and CHM format
$9.99 · In-app purchases
PRICE
$9.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 3.8
8 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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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 CHMate+: EPUB & CHM 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
Expand support to include more file formats like PDF.
Assumption to check: Limited format support for digital books
Validate with people who use this workflow before building.
Hypothesis 2
Optimize file handling and rendering for larger EPUB/CHM files.
Assumption to check: Inconsistent performance with large files
Validate with people who use this workflow before building.
Hypothesis 3
Provide more themes and font settings for users.
Assumption to check: Lack of customization options for reading experience
Validate with people who use this workflow before building.
Hypothesis 4
Offer a one-time purchase option in addition to subscription.
Assumption to check: Subscription model may deter some users
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
CHMate is an amazing way to read eBooks for EPUB and CHM format. With CHMate, You can organize your files into personal collections, add bookmarks and notes to your favorite passages, and find the desired text anywhere in your book. iCloud features • Organize your CHM documents into personal Collections that appear on all your devices • Keep bookmarks, highlights, notes, and your current page up-to-date everywhere using iCloud Great ways to read • Customizable fonts for heading, body text and code snippets, adjustable line height. • Fast scrolling, never be lagged with the pagination. • Highlight your favorite passages and add notes with the built-in bookmarking features • Share quotes, or thoughts about your favorite book with friends on Facebook, X, Messages, or Mail • Find a word, character, or phrase anywhere in your book with the built-in search feature • Gathering and show all images inside a page • Easily adjust your screen brightness to find the perfect lighting for any environment • Add files with desktop web browser or iTunes File Sharing
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
expo-file-system
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.
