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
National Grid
The National Grid mobile app makes it easier to securely manage your account from anywhere
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.8
12,161 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/
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.
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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 National Grid: map the core Utilities 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
Improve navigation with clearer labels and visual cues.
Assumption to check: Users report difficulty in navigating between sections.
Validate with people who use this workflow before building.
Hypothesis 2
Introduce a bottom tab bar for quick access to all main features.
Assumption to check: Some features may be hidden or hard to find.
Validate with people who use this workflow before building.
Hypothesis 3
Provide more comprehensive outage details and real-time updates.
Assumption to check: Limited information on outage details.
Validate with people who use this workflow before building.
Hypothesis 4
Make subscription options more visible and understandable.
Assumption to check: In-app purchase options are not clearly presented.
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
The National Grid mobile app makes it easier to securely manage your account from anywhere. Set up biometrics so you can access your account quickly and securely. With biometrics, you can sign in without having to enter your username and password again. Once you’re signed in, you can easily: • View essential account and billing information • Enroll in paperless billing • View and download a PDF of your current bill • Schedule a payment in-app or via Speedpay • Find nearby payment locations • Report a power outage or gas emergency • View the outage map • Explore your usage Now you can schedule a payment with your bank account, without having to leave the app. Use a new or saved bank account to pay your current bill, account balance or any other amount, just like you would on our website. We’ve also made it easier to report power outages and gas emergencies — with our mobile app, you’ve got access to emergency support right at your fingertips.
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
Victory Native
Axios
React Navigation
React Native Async Storage
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.
