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
Universe in a Nutshell
The range of size in the universe, from the tiniest particles to the epic galaxies - we take you on a journey of size that lets you explore it all with a single swipe
$2.99 · In-app purchases
PRICE
$2.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.9
2,509 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 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/
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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 Universe in a Nutshell: map the core Education 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
Implement gamified quizzes with interactive elements and instant feedback.
Assumption to check: Limited interactivity and engagement in quizzes
Validate with people who use this workflow before building.
Hypothesis 2
Add forums or chat features for users to discuss topics.
Assumption to check: Lack of community features for discussion
Validate with people who use this workflow before building.
Hypothesis 3
Introduce offline mode with downloadable content.
Assumption to check: Requires internet connection for all content
Validate with people who use this workflow before building.
Hypothesis 4
Provide advanced analytics on user performance and progress.
Assumption to check: No detailed performance tracking
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
The range of size in the universe, from the tiniest particles to the epic galaxies - we take you on a journey of size that lets you explore it all with a single swipe. How big is a planet, compared to a human? And how small is an atom really? You can’t fully wrap your head around the scope of things by just reading about them – so this app lets you experience them in comparison to get a feeling for their true scale. By simply swiping you can zoom in and out all the way from the world of fundamental particles up to the largest stars at the edge of the observable universe. Seamless zooming between the scales of 10^-35 meters to 10^26 meters (no math required) Amazing fun facts for various scale levels, like the smallest bacterium and the largest black hole Tap any object for an explanation of what it is and how it works Beautifully animated illustration of more than 250 objects Original Kurzgesagt music to complement your experience
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
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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.
