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
Mahjong Cash
Mahjong Cash: A Calm Journey of Skill and Good Fortune
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.9
28,137 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's included17 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 Mahjong Cash: map the core Games 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
Introduce new game modes and seasonal events to engage users.
Assumption to check: Limited game modes can lead to player boredom.
Validate with people who use this workflow before building.
Hypothesis 2
Offer more earning options through gameplay to reduce reliance on purchases.
Assumption to check: In-app purchases may frustrate users.
Validate with people who use this workflow before building.
Hypothesis 3
Limit ad frequency and offer ad-free gameplay as a premium option.
Assumption to check: Ads can disrupt gameplay experience.
Validate with people who use this workflow before building.
Hypothesis 4
Implement social features like friend challenges and chat.
Assumption to check: Lack of community features for social interaction.
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
Mahjong Cash: A Calm Journey of Skill and Good Fortune Game Overview Welcome to Mahjong Cash, where the elegance of classic Mahjong meets the excitement of real rewards. Step into a serene oriental garden filled with floating lanterns, drifting bamboo leaves, and gentle guzheng melodies. Here, peaceful beauty meets mindful challenge, offering a place to unwind while putting your skills to work. Core Gameplay Mahjong Cash keeps the timeless charm of Mahjong tile-matching: clear pairs, plan your moves, and aim for a flawless board. Every match is a moment of clarity, and every smart decision can lead to greater rewards. Whether you are relaxing for a short break or enjoying longer play sessions, Mahjong Cash brings both calm focus and meaningful satisfaction. Art Style The game is crafted in a refined Eastern aesthetic, with ink-brush patterns, carved jade textures, and smooth transitions. Every detail creates a gentle, poetic world that feels soothing and inviting — a tranquil retreat within your day. Game Value In Mahjong Cash, fun and rewards go hand-in-hand. The gameplay is simple to learn yet rich with depth, making every round fulfilling. Enjoy your time, sharpen your thinking, and win real cash prizes — all in one graceful, calming experience. Here, each victory is more than success — it's a moment of peace rewarded.
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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
Firebase
React Navigation
@react-native-async-storage/async-storage
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.
