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
Planetary-K-Index
Track the planetary K-index (Kp) — the standard measure of global geomagnetic activity.
$0.99 · In-app purchases
PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 5.0
4 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 included15 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 Planetary-K-Index: map the core Health & Fitness 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
Expand with more articles and resources.
Assumption to check: Limited educational content on solar activity
Validate with people who use this workflow before building.
Hypothesis 2
Introduce notifications for K index updates.
Assumption to check: Lack of user engagement features like notifications
Validate with people who use this workflow before building.
Hypothesis 3
Add features to share K index data on social media.
Assumption to check: No social sharing options
Validate with people who use this workflow before building.
Hypothesis 4
Enhance UI/UX for a more appealing look.
Assumption to check: Basic design that may not attract users
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
Track the planetary K-index (Kp) — the standard measure of global geomagnetic activity. Planetary K-Index shows live Kp from NOAA, official charts from GFZ Helmholtz Centre for Geosciences, and related space-weather products so you can see quiet conditions, active periods, and geomagnetic storms at a glance. WHAT YOU GET • Kp — estimated planetary K-index with scrubbable bars, conditions, and a 24-hour forecast • NOAA — station K & A indices, Boulder magnetometer, geospace, ACE, and aurora maps • Europe · GFZ — official Kp nowcast charts, Hp30, daily plots, Bartels diagram, plus Poland INTERMAGNET magnetograms (Belsk & Hel) • Pull to refresh on live data and chart screens WHY Kp MATTERS The K-index (and planetary Kp) characterizes disturbances in Earth’s magnetic field. Space weather agencies use it for geomagnetic alerts and warnings. Higher Kp values mean stronger activity — and better chances of aurora at lower latitudes during storms. FROM THE MAKERS OF QUICK SCHUMANN CHECK A focused companion for people who follow Kp, geomagnetic storms, and space weather — without the clutter. Data courtesy of NOAA SWPC, GFZ Helmholtz Centre for Geosciences, and IGF PAS (INTERMAGNET).
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
axios
victory-native
react-navigation
shadcn/ui
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.
