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
3 Minute Step Test - DIY Fitness Assessment
*** The easiest and quickest way for ANYONE to measure their health and fitness
$4.99 · In-app purchases
PRICE
$4.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 2.3
3 ratings · Below Average
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 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 3 Minute Step Test - DIY Fitness Assessment: 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
Add more analytics and personalized feedback.
Assumption to check: Limited features for tracking fitness progress
Validate with people who use this workflow before building.
Hypothesis 2
Enhance UI/UX with better visuals and gamification.
Assumption to check: Low user engagement due to simplistic design
Validate with people who use this workflow before building.
Hypothesis 3
Implement community challenges and social sharing.
Assumption to check: Lack of social features
Validate with people who use this workflow before building.
Hypothesis 4
Simplify subscription options and clarify benefits.
Assumption to check: Confusing paywall
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 easiest and quickest way for ANYONE to measure their health and fitness. You don't need to be an athlete to complete the step test. *** The 3 Minute Step Test or Queens College Step test is one of many variations of step test procedures, used to determine aerobic fitness. The test is an easy to administer sub-maximal test of cardiovascular endurance and this app does all the work for you so you can concentrate on your test. *** Procedure of 3 Minute Step Test *** 1.) The athlete steps up and down on the platform at a rate of 22 steps per minute for females and at 24 steps per minute for males. Pace is set by the internal metronome inside the app. The subjects are to step using a four-step cadence, 'up-up-down-down' for 3 minutes. 2.) The athlete stops immediately on completion of the test, where they are guided through the counting of their heart rate for 15 seconds. 3.) The user then enters their HR and this information is then used to determine the level of aerobic fitness and a predicted V02max. The theory is that the lower your heart rate on completion of activity, the higher your aerobic fitness base.
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
Zustand
React Navigation
Expo Sensors
React Native Reanimated
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.
