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
Situps Extreme: 400 Sit ups Workout Trainer XT Pro
Extreme Situps: build amazing abs!
$1.99 · In-app purchases
PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.8
21 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 Situps Extreme: 400 Sit ups Workout Trainer XT 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
Include more diverse workouts and customizable routines.
Assumption to check: Limited variety of exercises
Validate with people who use this workflow before building.
Hypothesis 2
Add community challenges and sharing options.
Assumption to check: Lack of social features
Validate with people who use this workflow before building.
Hypothesis 3
Implement HealthKit/Google Fit integration for tracking.
Assumption to check: No integration with fitness trackers
Validate with people who use this workflow before building.
Hypothesis 4
Provide a more cohesive design with consistent styles and spacing.
Assumption to check: Inconsistent UI elements
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
Extreme Situps: build amazing abs! This app will train you to be able to do 400 situps (8 sets of 50 situps each, in a row). ● Get ready to have a great body! ----- WHO IS THIS APP FOR? ----- This app is for people who already can do 8 sets of 25 situps each. If you can't, please consider our 0-200 situps app. It will get you there. ----- ABOUT THE APP ----- This app will train you to do 400 situps in 8 sets of 50 situps each. You will begin from 8 sets of 25 situps, and over the course of 10 weeks will increase the effort until you hit 400 situps. When you are done, you will be much stronger and have much better looking abs. When you start a workout, you turn on your favorite music, and then the app's audio coach tells you exactly how many situps to do, when to rest, and when to resume. The app also keeps you motivated, which is the key to success and the true magic of the app. The plan is achievable and enjoyable even by people that never liked to exercise, and you will earn wins and badges as you go along. With this app, you will have better abs. Extreme Situps is made by experts, the same people that built the awesome 5K & 10K Runner apps, the 0 to 200 situps app, and many others. COACHING ● guided by your personal audio coach ● starts easy and slowly increases the situps ● straight & simple, nothing to learn ● integrated with Apple Health MUSIC ● listen to your music while exercising ● audio coach gently blends in when needed ● compatible with ALL music apps MOTIVATION ● earn wins and badges ● share your wins on Facebook, Twitter, mail ● meet other trainees on our Facebook community ● motivational quotes for your mind & body SUCCESS ● Only 20 mins a day, 3 days a week, 10 weeks ● Designed to make anyone succeed ● Extensive guidance for beginners ● Answers to all common questions AND THERE'S MORE ● stretching & warmup videos ● male & female audio coaches ● detailed information & guidance ● and there is more... Supported Devices: ● iPhone & iPod touch (all models) ● iPad: runs as an iPhone/iPod app ● Privacy Policy: http://www.fitness22.com/privacy ● Terms of use: http://fitness22content.com/Components/WebPages/TermsOfUse/TermsOfUse.html ----- CONTACT US ----- ● Dear customers, we are here for you! [email protected]
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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
TypeScript
Axios
react-native-reanimated
@react-native-community/async-storage
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.
