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
RiverApp - River levels
Get quick access to the latest river levels, flows and conditions across the US and more than 20 other countries worldwide.
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.8
5,282 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 RiverApp - River levels: map the core Weather 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 set personalized alerts based on specific river levels.
Assumption to check: Limited customization options for alerts
Validate with people who use this workflow before building.
Hypothesis 2
Implement offline mode to view last known river levels without internet.
Assumption to check: Lack of offline functionality
Validate with people who use this workflow before building.
Hypothesis 3
Add graphs or charts to visualize historical data over time.
Assumption to check: No visual representation of water level changes
Validate with people who use this workflow before building.
Hypothesis 4
Optimize backend calls to provide more frequent updates.
Assumption to check: Slow data refresh rate
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
Get quick access to the latest river levels, flows and conditions across the US and more than 20 other countries worldwide. RiverApp gives you access to one of the world’s most comprehensive hydrometric datasets, with data from over 40,000 monitoring stations. Whether you kayak, canoe, packraft, paddleboard, fly fish, surf rivers, manage irrigation, operate hydropower infrastructure or monitor flood risk, RiverApp helps you stay informed with reliable, easy-to-read river data. FREE FEATURES ‣ Current water levels and flows for over 20,000 rivers ‣ Water temperature data where available ‣ Detailed maps of hydrometric stations and whitewater sections ‣ Custom alerts for each station when a defined level or flow is reached ‣ Favourite stations and whitewater sections for quick access to the latest readings and conditions FREE FEATURES FOR WHITEWATER SPORTS ‣ More than 4,000 referenced whitewater sections ‣ Section conditions based on current water level or flow ‣ Detailed section maps with quick access to put-in and take-out points ‣ Hazards, rapids and other points of interest, including photos where available ‣ Information on difficulty, length and average gradient ‣ Community-based addition and editing of whitewater sections RIVERAPP PREMIUM Unlock additional tools for deeper river monitoring and trip planning: ‣ Historical water level and flow data going back several years ‣ Forecasts for selected stations ‣ Satellite map layers from multiple providers, with comparison tools ‣ Customizable Home Screen Widgets to keep your favourite river gauges visible at a glance ‣ Monthly streamflow statistics to understand seasonal variations and plan river trips at the right time and place DATA SOURCES RiverApp brings together data from over 100 official and public hydrometric sources worldwide, including, among others: NVE California Data Exchange Center Government of Canada — Wateroffice USGS NOAA PEGELONLINE — www.pegelonline.wsv.de HVZ Baden-Württemberg HDN Bayern Kanton Bern Ennskraftwerke Land Kärnten Land Niederösterreich Regione Piemonte HVZ Rheinland-Pfalz Český hydrometeorologický ústav HVZ Sachsen-Anhalt Land Salzburg Scottish Environment Protection Agency Slovak Hydrometeorological Institute Agencija Republike Slovenije za okolje HWZ Steiermark BAFU HNZ Thüringen Land Tirol Shoothill Vigicrues Serveur de données hydrométriques temps réel du bassin Rhône-Méditerranée Land Vorarlberg Bureau of Meteorology — Australia DISCLAIMER RiverApp is an independent application and is not affiliated with the listed organizations unless explicitly stated. RiverApp and the listed data providers shall not be held liable for any errors, omissions, delays or interruptions in the information provided, nor for any loss, injury or damage of any kind resulting from its use. End-user license agreement: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
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.
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BUILD KIT DIFFICULTY
Advanced
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.
