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
Heat Index & Category Calc
• Featured by Apple App Store in Weather > What’s Hot for the iPad in 108 countries.
$0.99 · In-app purchases
PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 3.5
2 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.
Build your own version
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.
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 Heat Index & Category Calc: map the core Weather 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
Add features like location-based weather, severe weather alerts, and extended forecasts.
Assumption to check: Limited functionality compared to more comprehensive weather apps
Validate with people who use this workflow before building.
Hypothesis 2
Simplify UI/UX and improve layout for better usability.
Assumption to check: User interface can be cluttered
Validate with people who use this workflow before building.
Hypothesis 3
Implement real-time updates for weather data.
Assumption to check: Inconsistent data refresh rates
Validate with people who use this workflow before building.
Hypothesis 4
Allow users to customize alerts and display preferences.
Assumption to check: Limited customization options
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
• Featured by Apple App Store in Weather > What’s Hot for the iPad in 108 countries. Heat Index & Category Calculator is a straightforward weather app for checking how hot it really feels when temperature and humidity climb. It gives you a quick answer without making you dig through charts or guess at the risk. - Calculate heat index from air temperature and relative humidity. - See the result in both Fahrenheit and Celsius. - Pull current NOAA weather for your location. - Load the five closest NOAA stations and switch between them. - View station observations and forecast details. - Compare military, OSHA, NOAA, and athletic heat bands. - Keep inputs saved locally so repeat checks are fast. - Use manual entry when you already know the numbers. - Use it for outdoor work, sports, travel, yard work, and summer planning. Heat Index Calculator stays focused on the information people actually need: - what the heat index feels like - whether the day is getting risky - which station is giving the best local reading - what the forecast looks like for the rest of the day If you want a simple heat index calculator with NOAA weather, station data, and a clean layout, this app keeps it practical.
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.
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BUILD KIT DIFFICULTY
Starter
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.
