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
NDTimer - Long Exposure
NDTimer is the ultimate companion for photographers seeking precise control over their long-exposure shots! The app simplifies the complex task of calculating ND filter exposure times, allowing you to focus on capturi...
$1.99 · In-app purchases
PRICE
$1.99
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 included15 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 NDTimer - Long Exposure: map the core Photo & Video 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
Add features like custom ND filter creation and cloud backup for settings.
Assumption to check: Limited functionality for advanced photography settings
Validate with people who use this workflow before building.
Hypothesis 2
Implement visual and sound alerts to notify users when timer ends.
Assumption to check: Lack of user feedback for timer completion
Validate with people who use this workflow before building.
Hypothesis 3
Allow users to save and manage multiple timer presets.
Assumption to check: No support for multiple timers or presets
Validate with people who use this workflow before building.
Hypothesis 4
Include an onboarding tutorial or help section within the app.
Assumption to check: Unclear instructions 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
NDTimer is the ultimate companion for photographers seeking precise control over their long-exposure shots! The app simplifies the complex task of calculating ND filter exposure times, allowing you to focus on capturing stunning images with ease. Key Features: - Multi-Filter Support: Whether you're stacking multiple ND filters or using a combination of different types, NDTimer has you covered. Effortlessly calculate exposure times for various filters to achieve the perfect balance of light in your photos. - Custom Filter Settings: Tailor the app to your unique setup with our customizable filter feature. Input the specific details of your custom filter, and let the app do the rest, ensuring accurate exposure calculations every time. - Intuitive Countdown Timer: A sleek and easy-to-read countdown timer keeps you informed about the remaining exposure time. Watch as your long-exposure masterpiece unfolds before your lens. - User-Friendly Interface: The user-friendly interface makes navigating through the app a breeze, ensuring a smooth experience for both amateur and professional photographers. - Precision and Accuracy: NDTimer is developed to calculate the optimal long-exposure time allowing you to capture the perfect shot, every time.
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
React Native
Expo
Zustand
react-navigation
expo-av
react-native-reanimated
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.
