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
When Was This Opened?
Never wonder if that opened food is still safe to eat! "When Was This Opened?" helps you quickly check how long various foods stay fresh after opening, based on FDA and USDA guidelines.
$0.99 · In-app purchases
PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 5.0
1 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.
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 included16 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 When Was This Opened?: 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
Implement batch tracking features.
Assumption to check: Limited functionality for tracking multiple items at once.
Validate with people who use this workflow before building.
Hypothesis 2
Add push notifications to alert users.
Assumption to check: No notifications for items nearing expiration.
Validate with people who use this workflow before building.
Hypothesis 3
Integrate with grocery shopping apps for ease of use.
Assumption to check: Lack of integration with grocery lists or shopping apps.
Validate with people who use this workflow before building.
Hypothesis 4
Offer a one-time purchase option alongside subscriptions.
Assumption to check: Subscription model can deter users who prefer one-time purchases.
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
Never wonder if that opened food is still safe to eat! "When Was This Opened?" helps you quickly check how long various foods stay fresh after opening, based on FDA and USDA guidelines. SIMPLE & FAST • Browse multiple food categories • Select your food item • Indicate when you opened it • Get instant safety guidance COMPREHENSIVE DATABASE • Dairy products • Meats & poultry • Seafood • Leftovers • Sauces & condiments • Produce • Bakery items • Prepared foods SCIENCE-BACKED All recommendations are based on conservative estimates from official FDA and USDA food safety guidelines. The app includes direct links to these sources so you can verify the information. PRIVACY FIRST This app does not collect, store, or transmit any personal data. All calculations happen locally on your device. No account required, no tracking, no ads. TRUST YOUR SENSES While this app provides helpful guidelines, always use your best judgment. If food looks, smells, or tastes unusual, it's best to discard it. This app is not a substitute for professional food safety advice. Perfect for reducing food waste while staying safe!
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
Supabase
Zustand
React Navigation
@supabase/supabase-js
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.
