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
Lumy
Lumy is a modern sun tracker + outdoor activity planner.
$7.99 · In-app purchases
PRICE
$7.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.8
2,314 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
Make this idea yours
A product spec, screen plans, and build steps for your coding agent.
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What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
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 Lumy: map the core Photo & Video 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 customizable tracking options based on user preferences.
Assumption to check: Limited functionality for adjusting sun tracking settings
Validate with people who use this workflow before building.
Hypothesis 2
Implement offline mode for users in remote areas.
Assumption to check: Lack of offline capabilities
Validate with people who use this workflow before building.
Hypothesis 3
Introduce a free tier with basic features to attract more users.
Assumption to check: Subscription model may deter users
Validate with people who use this workflow before building.
Hypothesis 4
Enable users to share sun tracking data directly within the app.
Assumption to check: Limited sharing options for sun position data
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
Lumy is a modern sun tracker + outdoor activity planner. - Perfect lighting for photos or videos? Done. - Sunrise hike or sunset walk? Easy. - Outdoor yoga or sunlight breaks? Covered. Whether you’re chasing golden hour* or keeping an eye on moon phases for a night under the stars, Lumy helps you make the most of natural light. Now redesigned from the ground up - Lumy feels more personal, purposeful, and in sync with how we live. Introducing Modes: Switch between profiles like Daily, Photography, or Meditation to shape Lumy around your routine. See only what matters to you. Lumy also supports iOS’s State of Mind feature, offering sunlight suggestions based on your mood entries in the Health app - a gentle nudge to step out and connect with nature. And with weather forecasts for the next seven days, you can plan with confidence. Lumy calculates all sun and moon data entirely on-device. No tracking. No server calls. Only the weather needs internet. Lumy works seamlessly across iPhone, iPad, Apple Watch, Apple TV, and HomePod. One purchase, full family access. Features - Modes: Switch profiles based on your needs... from weekday planning to weekend golden hour. - Sun + Moon Tracking: Accurate data, solar compass, and future predictions. - Season Info: Both astronomical and meteorological seasons. - Remainders: Custom repeatable notifications. - Apple Watch: Complications, Double-tap, and Live Activities. - Widgets + Control Center: Quick access via Smart Stack and more. - Interaction Upgrades: Time travel slider, Quick Access Button, fluid animations. - Visual Feel: Simulated light, shimmering glows, and enhanced Classic visuals. - Accessibility: VoiceOver, Dynamic Type, Reduce Motion, and more. - Privacy First: Fully offline (except weather). Your data stays with you. - Localization: Available in Japanese, Chinese, French, and German. Lumy helps photographers, outdoor lovers, and wellness seekers stay in sync with the sun and moon. *What's Golden Hour? Golden Hour (or Magic Hour) is the short time after sunrise or before sunset when the light is soft, warm, and perfect for capturing stunning photos or videos. Sun Information Available: Sunrise, Sunset, First Light, Last Light, Golden Hour, Blue Hour, Astronomical Twilight, Nautical Twilight, Civil Twilight, Solar Noon, Solar Midnight. Moon Information Available: Moonrise, Moonset, Altitude, Azimuth, Transit, Transit Elevation, Weekly Moon Phase, Next Full Moon, New Moon, First Quarter, Last Quarter. Got feedback or suggestions? We’d love to hear from you! Reach out at [email protected].
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-maps
@react-native-animated
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.
