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
75 Hard
|| Requires Subscription ||
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.6
6,342 ratings · Top 15%
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 included18 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 75 Hard: 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
Allow users to create custom tasks and challenges.
Assumption to check: Limited customization options for tasks and challenges
Validate with people who use this workflow before building.
Hypothesis 2
Implement features for users to interact, share progress and challenge each other.
Assumption to check: Lack of social interaction features
Validate with people who use this workflow before building.
Hypothesis 3
Introduce an onboarding tutorial to guide users through app features.
Assumption to check: Overwhelming for new users
Validate with people who use this workflow before building.
Hypothesis 4
Add push notifications for daily task reminders.
Assumption to check: No reminders for task completion
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
|| Requires Subscription || 75 HARD is how you win the war with yourself. Are you stuck in life? You feel like no matter what you do, your career, fitness, and relationships just aren’t where you thought they would be? Feel like you are not reaching your full potential? This program is for you. Maybe you’ve tried the fad diets, read the latest trendy self help book, or forked over your hard-earned cash for seminars and courses that promised to teach you the magical secret to success. Yet even after all this, you still fail to make any real progress. Why? Here’s the real secret. YOU are the key. If you haven’t developed the traits of mental toughness needed for success in any area of your life, all these other things will get you nowhere. What are these traits? Confidence. Grit. Fortitude. Self Belief. Self Worth Discipline. Endurance. The unbreakable will to WIN. Over the course of 75 days, this program will start you down the path to becoming a person who is capable of achieving your goals by developing these winning character traits. Is it complicated? No. Is it easy? Definitely not. In fact, it’s probably the hardest thing you’ve ever done. Will it change your life forever? Without a doubt. Are you ready to win the war within yourself? This program requires Zero Compromises. Zero Substitutions. With the 75 Hard app, you can: - Track your daily progress - Set custom reminders for your daily tasks - Take and review your daily progress pics - Share your progress to your Instagram Story or any way you like - Save personal notes on every day - See all your progress from every attempt - Continue past 75 Hard to complete the full year Live Hard program Already started the 75 Hard Program? No problem! We’ve made it easy for you to pick up at your current progress point. We’re working to continuously update the app with new features and updates to provide the best experience for you as you make progress. View terms and conditions: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
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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
Zustand
React Navigation
react-native-svg
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.
