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
Delta - Adaptive TDEE
Delta – Adaptive TDEE Tracker helps you manage weight, calories, and nutrition with precision
$2.99 · In-app purchases
PRICE
$2.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
N/A
No ratings yet
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 included14 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 Delta - Adaptive TDEE: 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
Simplify the input process with clear guidance and tooltips.
Assumption to check: Users often find TDEE calculators too complex or confusing.
Validate with people who use this workflow before building.
Hypothesis 2
Introduce customizable goals based on user preferences.
Assumption to check: Lack of personalized features for different fitness goals.
Validate with people who use this workflow before building.
Hypothesis 3
Implement a robust progress tracking feature with graphs.
Assumption to check: Limited tracking capabilities for progress over time.
Validate with people who use this workflow before building.
Hypothesis 4
Clearly outline what premium features are available and their benefits.
Assumption to check: In-app purchase confusion regarding what features are included.
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
Delta – Adaptive TDEE Tracker helps you manage weight, calories, and nutrition with precision. By combining real-world data, activity levels, and personal goals, Delta estimates your Total Daily Energy Expenditure (TDEE) and generates dynamic daily calorie targets. Why use Delta? Traditional calorie and weight-tracking apps rely on static formulas. But life isn’t static — your energy needs aren’t either. Delta calculates your TDEE dynamically using your logged weight and calorie data. Minor fluctuations are smoothed out, giving a more accurate estimate of daily intake for maintenance or weight loss. Key Features: • Track daily weight and calorie intake • Adaptive TDEE targets that adjust as you log more data • Trend analysis and smoothing for real progress • Science-backed formulas combined with real-world tracking Why "Delta"? • Δ between your current weight and goal drives energy needs • Δ between calories in and out shapes your progress • Δ between real-world TDEE and target guides daily intake • Δ between existing apps and what we needed inspired Delta Delta is your smart companion for weight management, nutrition tracking, and achieving your goals - personalised, adaptive, and dynamic.
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
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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.
