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
Vita Mahjong
Vita Mahjong – Free Mahjong Solitaire & Brain Game for Seniors!
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.9
1,706,512 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 Vita Mahjong: 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 more varied levels and challenges.
Assumption to check: Repetitive gameplay can lead to boredom.
Validate with people who use this workflow before building.
Hypothesis 2
Add features for inviting friends and sharing scores.
Assumption to check: Limited social features for competing with friends.
Validate with people who use this workflow before building.
Hypothesis 3
Provide an ad-free premium option.
Assumption to check: Ads can disrupt gameplay experience.
Validate with people who use this workflow before building.
Hypothesis 4
Clarify scoring mechanics and provide hints.
Assumption to check: Some users find the scoring system unclear.
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
Vita Mahjong – Free Mahjong Solitaire & Brain Game for Seniors! Relax, Train Your Brain, and Enjoy Classic Tile-Matching Fun! Looking for a senior-friendly mahjong solitaire game with large tiles and easy controls? Vita Mahjong is the #1 offline puzzle game designed for older adults and casual players! Enjoy hundreds of levels, memory-boosting challenges, and a calming experience – perfect for tablets and phones! Why 500,000+ Players Love Vita Mahjong: 1.Classic Mahjong Solitaire – Traditional tile-matching gameplay with modern twists! 2.Large, Clear Tiles – Reduce eye strain with senior-friendly design (No squinting!). 3.Brain-Training Mode – Improve memory & focus with special cognitive puzzles! 4.Play Offline, Anywhere – No Wi-Fi? No problem! Perfect for travel or relaxing at home. 5.Daily Brain Exercises – New puzzles every day to keep your mind sharp! 6.Hints & Undo – Stuck? Use smart tools to solve tough levels stress-free. 7.Optimized for All Devices – Smooth gameplay on iPhone, iPad tablets! How to Play (Simple Rules!): 1.Tap Matching Tiles – Remove pairs of identical tiles. 2.Clear the Board – Strategize to unlock blocked tiles! 3.Level Up! – Puzzles get trickier as you progress – train your brain! Perfect For: 1.Seniors & Elderly Players – Easy controls, no time limits, and large visible tiles. 2.Casual Gamers – Relax and unwind with soothing puzzles. 3.Brain Training Fans – Scientifically designed to boost memory and logic! --- Stay Connected & Safe Support: [email protected] Privacy Policy: https://vitastudio.ai/pp.html Terms of Service: https://vitastudio.ai/tos.html EULA: https://vitastudio.ai/tos.html Join 50k+ Players on Facebook: https://www.facebook.com/groups/vitastudio Official Website: https://www.vitastudio.ai/
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
react-native-reanimated
expo-router
Firebase
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.
