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
Mortgage Payment Calc Pro
If you are the person who:
$1.99 · In-app purchases
PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.0
6 ratings · Top 30%
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.
Build your own version
Build Kit
Make this idea yours
A product spec, screen plans, and build steps for your coding agent.
First kit free with a verified email
Add to a Remix
Combine features and design from your favorite apps.
Kit ready. Verify your email to download it.
Generating… usually about a minute.
Make it yours Optional
What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
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/
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.
JavaScript is required to complete mailbox verification.
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 Mortgage Payment Calc Pro: map the core Finance workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
Preview ready. Verify your email to reveal and copy the full prompt.
JavaScript is required to complete mailbox verification. Return to this prompt preview.
Continue in Rork >
Affiliate link: CloneChart may earn a commission at no extra cost
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 additional tools like amortization schedules or comparison with different rates.
Assumption to check: Limited features beyond basic calculations.
Validate with people who use this workflow before building.
Hypothesis 2
Implement a modern, clean UI with better UX design.
Assumption to check: User interface feels outdated.
Validate with people who use this workflow before building.
Hypothesis 3
Include features to save history and share results easily.
Assumption to check: No ability to save or share calculations.
Validate with people who use this workflow before building.
Hypothesis 4
Allow users to customize their experience with themes and settings.
Assumption to check: Lack of customization options.
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
If you are the person who: * Prepare or wish to buy a house; * Have mortgage loans; * Is a housing agency; * want to calculate or manage loans etc. You will need this smart and comprehensive app to calculate the payment each cycle, payoff date, total payment, total interest, affordability, the payment schedule and prepayment etc, and also to manage your loans, track loans’ process and share amortization schedule. There are three calculators: ⁃ Mortgage calculator; ⁃ Loan calculator; ⁃ Affordability calculator. You can save the results for further comparison or consideration. Input value could be house value, frequency, term, interest rate, start date, annual property tax, annual home insurance and PMI. The Frequency could be Weekly, Bi-Weekly, Monthly, Quarterly and Yearly. How you can manage your loans? ⁃ Check your loans in one place. ⁃ Check the process of your total loans and each loan. ⁃ Set notification for each loan. ⁃ Check the payment, principal, interest and balance of each cycle. ⁃ Mark the schedule as paid after it been paid. ⁃ Add extra payment and get the analysis about the new payoff date, new total payment and how much you can save. Other features: ⁃ Set your own currency. ⁃ iCloud and Dropbox backup and restore. ⁃ Passcode protection. ⁃ Supports universal version. If you have any question or suggestion, please send email to [email protected].
Written user reviews are not shown here. Check current App Store reviews >
Screenshots
< Scroll to see more >
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
React Navigation
react-native-paper
@react-native-async-storage/async-storage
TypeScript
BUILD KIT DIFFICULTY
Intermediate
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.
