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
Try Shuangpin - Double Pinyin
Try Shuangpin is a Double Pinyin typing practice app for iPhone, iPad, Mac, and the web.
$0.99
PRICE
$0.99
No in-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.3
7 ratings · Top 30%
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 included
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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Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Try Shuangpin - Double Pinyin: 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
Provide detailed explanations for mistakes to enhance learning.
Assumption to check: Limited feedback on incorrect input.
Validate with people who use this workflow before building.
Hypothesis 2
Include more diverse exercises and phrases for practice.
Assumption to check: Few typing exercises available.
Validate with people who use this workflow before building.
Hypothesis 3
Implement a dark mode for improved usability in low-light conditions.
Assumption to check: No dark mode option.
Validate with people who use this workflow before building.
Hypothesis 4
Allow users to customize settings to better suit their learning preferences.
Assumption to check: Lack of user customization features.
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
Try Shuangpin is a Double Pinyin typing practice app for iPhone, iPad, Mac, and the web. Start with layout drills, move into word practice and article typing, and build a steady Chinese typing routine. 1. What is Double Pinyin? Double Pinyin (Shuangpin) maps every pinyin syllable to exactly two keystrokes, making Chinese typing faster and more consistent. It's built into the iOS system keyboard — no third-party keyboard needed. 2. Who it is for • Learners switching from full pinyin to Double Pinyin • Users practicing common Double Pinyin layouts and typing rhythm • People who want structured drills, article practice, and speed tests 3. Core features • Layout drills for initials, finals, and key mapping • Word practice for common vocabulary • Article practice with classical texts and custom text import • Speed tests for accuracy, pace, and consistency • Game mode for lighter repetition 4. Supported layouts Xiaohe · Natural Code · Microsoft · Sogou · Smart ABC · Pinyin Jiajia · Ziguang · Guobiao plus Xiaohe Yinxing and Huma Yinxing (PRO) 5. More to explore • 1,400+ practice texts (Tang poems, Song ci, Book of Songs, classical prose, Yuefu poetry) • 11 keyboard sound options and haptic feedback • Available on iPhone, iPad, Mac, and Web Website: ulpb.app Email: [email protected] Terms of Service (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://ulpb.app/privacy Terms of Service: https://ulpb.app/terms
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
react-navigation
@react-native-async-storage/async-storage
react-native-reanimated
BUILD KIT DIFFICULTY
Not assessed in a Build Kit yet.
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.
