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
Tip Calculator % Gold
This free tip calculator features fast bill entry and splitting, ideal for those dining out, on a date, or having drinks with friends.
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.8
59,486 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 included14 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 Tip Calculator % Gold: map the core Food & Drink 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
Simplify access to history with a dedicated tab or button.
Assumption to check: Users find it hard to navigate to past calculations
Validate with people who use this workflow before building.
Hypothesis 2
Allow users to set multiple default percentages.
Assumption to check: Some users want more customization on tip percentages
Validate with people who use this workflow before building.
Hypothesis 3
Streamline settings with collapsible sections.
Assumption to check: The UI can be cluttered with too many settings
Validate with people who use this workflow before building.
Hypothesis 4
Implement a currency converter for global users.
Assumption to check: Limited support for different currencies
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
This free tip calculator features fast bill entry and splitting, ideal for those dining out, on a date, or having drinks with friends. • Splits bill with ease! • Save $$$ by tipping an exact amount • Rounding feature! What our users are saying... "Simple. To the point. Beautiful." "Especially love the split function" "Perfect and easy" "Easy to read" This app is supported by advertising. By downloading, installing, and using this app you agree to our: Terms of Use: http://app.skolgames.com/p/terms-of-service.html Privacy Policy: https://app.skolgames.com/p/privacy-policy.html
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.
