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
PepCalc Pro
PepCalc Pro is a professional-grade concentration and measurement tracker built for clarity, precision, and privacy
$2.99 · In-app purchases
PRICE
$2.99
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.
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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 PepCalc Pro: 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
Incorporate social sharing and challenges to motivate users.
Assumption to check: Apps in this category often lack user engagement features.
Validate with people who use this workflow before building.
Hypothesis 2
Use pre-set values or sliders to simplify input.
Assumption to check: Complexity in data entry can deter users.
Validate with people who use this workflow before building.
Hypothesis 3
Add comprehensive charts and historical data tracking.
Assumption to check: Limited progress tracking features.
Validate with people who use this workflow before building.
Hypothesis 4
Create an interactive tutorial for first-time users.
Assumption to check: Inadequate onboarding for new users.
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
PepCalc Pro is a professional-grade concentration and measurement tracker built for clarity, precision, and privacy. Designed for meticulous research management, it combines deterministic calculations with a complete lifecycle system—all in a 100% offline-first environment. Manage your protocols with ease using the new visual calendar, bridge calculations directly to your inventory, and maintain a verifiable audit trail with "Show Math" transparency. No ads, no accounts, and no subscriptions. CORE FEATURES Precision Calculations - Calculate concentration and required volume with deterministic accuracy. - Visual unit gauge provides a quick "sanity check" for your measurements. - "Show Math" toggle: View exact formulas and intermediate values for total verification. New: Protocol Calendar & Scheduling - Dedicated visual roadmap for your schedules with custom color-coding. - Create recurring schedules linked to specific calculation snapshots. - On-device reminders ensure you stay on track with your protocol. Seamless Inventory Management - Track vials, remaining amounts, and expiration dates. - Instant Inventory Bridge: Create a matching inventory vial directly from a saved preparation. - Automatic decrement: Log a dose and your inventory updates instantly. - Low-stock and expiration alerts. Verifiable Records (History) - Record completed or skipped entries with timestamps and notes. - Ledger-style history: Every record is tied to an immutable "snapshot" of the math used at that time. - Simple, high-level summaries for recent activity and compliance. Designed for Trust & Privacy - Offline-first: Your data never leaves your device. - One-time purchase: All features included with no subscriptions or hidden fees. - Security: Optional App Lock via Face ID, Touch ID, or PIN. Professional Exporting - Export records as CSV or PDF with custom date-range filtering. - Perfect for external logs, lab notebooks, or personal record-keeping. IMPORTANT NOTICE PepCalc Pro is intended for informational and organizational purposes only. It does not provide medical advice, diagnosis, treatment, or prescriptions. All inputs, outputs, and decisions are the responsibility of the user. Verify all calculations independently.
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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
react-navigation
react-native-chart-kit
@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.
