App Overview

Mahjong Helper & Calculator icon

Mahjong Helper & Calculator

Michael Starling · Entertainment

Mahjong is an enjoyable game, played around the world

$0.99 · In-app purchases

PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
3.8
19 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 included17 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.

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.

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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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Mahjong Helper & Calculator: map the core Entertainment 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

Include additional scoring options and statistics for players.

Assumption to check: Limited features for advanced scoring calculations

Validate with people who use this workflow before building.

Hypothesis 2

Allow users to customize game settings and player profiles.

Assumption to check: Lack of user customization options

Validate with people who use this workflow before building.

Hypothesis 3

Simplify the UI for better navigation and user experience.

Assumption to check: User interface can be cluttered

Validate with people who use this workflow before building.

Hypothesis 4

Optimize the app for better performance on a wider range of devices.

Assumption to check: Inconsistent performance on older devices

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 is an enjoyable game, played around the world. However, for beginners (and even more experienced players!), calculating the value of a hand can be confusing. On top of that, payments between players after the value of each hand is calculated can also be tricky. Mahjong Helper aims to simplify the tasks of scoring and payments between games. It can also be used to keep a history of matches played, and to easily experiment with different methods of scoring. Features: * Multiple Matches * Beautiful, easy-to-read tiles. * Hand Scorer with intuitive tile/set-type selector (press, slide, and release to choose a tile) * Supports European Classical, Hong Kong, Japanese Modern / EMF Riichi (with Dora tiles and Red Fives), and Chinese Official (MCR / Competition) scoring * 4, 3, and 2 player scoring modes * Send scores from Hand Scorer to Score Sheet, or enter scores manually. * Score Sheet calculates payments between players, supports "Ready" declarations and counters in Japanese Mahjong. * see how the score is calculated on the "Scoring" panel - great for those learning the game, or just to double-check! * Supports seat rotation between rounds, or groups that prefer keeping the same positions throughout. * Share matches across devices - other players can keep a record of the match & contribute to scoring from their own devices. Requires a data connection. * Print score sheets to your AirPrint-enabled printer! I hope you like it!

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 Navigation
React Native Paper
Async Storage
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.