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
Finnish Marine Speed Limits
Maritime Speed Limits helps you stay aware of speed limits and other boating restriction areas in Finnish waters using official data provided by the Finnish Transport Infrastructure Agency (Väylävirasto).
$2.99 · In-app purchases
PRICE
$2.99
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.
Build your own version
Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
What's included16 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 Finnish Marine Speed Limits: map the core Navigation 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
Use prominent icons and colors to highlight speed limits.
Assumption to check: Apps lack clear speed limit displays
Validate with people who use this workflow before building.
Hypothesis 2
Offer comprehensive offline maps for better access.
Assumption to check: Limited offline functionality
Validate with people who use this workflow before building.
Hypothesis 3
Implement robust notification settings for users.
Assumption to check: Notifications may be unreliable
Validate with people who use this workflow before building.
Hypothesis 4
Simplify transitions and enhance user flow between screens.
Assumption to check: Difficult navigation between zones
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
Maritime Speed Limits helps you stay aware of speed limits and other boating restriction areas in Finnish waters using official data provided by the Finnish Transport Infrastructure Agency (Väylävirasto). Receive local notifications when you enter a new speed limit zone, even while the app is running in the background. Spend less time checking the map and more time focusing on safe boating. Features: • Official maritime speed limits and restriction areas • Background notifications when speed limits change • GPS speedometer • Built-in compass • Clean, easy-to-read map • One-time purchase — no subscriptions Whether you're cruising, fishing, or heading to your summer cottage, Maritime Speed Limits helps you stay informed about the restrictions along your route. This app is provided as a navigation aid only. The operator of the vessel is always responsible for complying with applicable regulations and navigating safely.
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
Supabase
react-navigation
@react-native-mapbox-gl/maps
react-native-paper
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.
