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
Zulu Time Widget - GMT/UTC
Full-featured and convenient Zulu Time App for iPhone, iPad and Apple Watch
$3.99 · In-app purchases
PRICE
$3.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.7
832 ratings · Top 15%
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 Zulu Time Widget - GMT/UTC: 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
Provide more customizable widget designs and sizes.
Assumption to check: Widget customization options are limited.
Validate with people who use this workflow before building.
Hypothesis 2
Simplify the subscription model and clarify benefits.
Assumption to check: In-app purchase system could be confusing.
Validate with people who use this workflow before building.
Hypothesis 3
Implement a more prominent and user-friendly history feature.
Assumption to check: Conversion history is not easily accessible.
Validate with people who use this workflow before building.
Hypothesis 4
Add support for converting between multiple time zones.
Assumption to check: No support for multiple time 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
Full-featured and convenient Zulu Time App for iPhone, iPad and Apple Watch. Get the current Zulu/GMT/UTC Time, UTC Date and offset anytime, in any time zone. Super quick and convenient tool for pilots, military personnel, sailors, etc. Includes iPhone/iPad app, Home Screen, Lock Screen Widgets and Apple Watch app with complications showing the Zulu hour right on the watch face. Includes a robust Mission/Event Timer for synchronizing with Zulu Time Events such as IFR clearance void times, rocket launches, flight plans, ICAO border crossings, military maneuvers and missions, etc. On iPad, Zulu Time fully support split view allowing you to run it alongside a navigation app, for instance. Also show seconds and the current GMT date. TAF style UTC date format is available as an option. Includes an easy-to-use converter tool to convert any time between Zulu time and your current local timezone in either direction. When on the phone with Flight Service on a trip through Canada, just swipe to bring up the Home Screen and find the current Zulu Time as a widget. If you have an Apple Watch, it's even easier! Just glance at your watch with the included complications. Leaving in 3.5 hours? Just slide the time slider on either the iPhone/iPad or Apple Watch Planner view forward to get the Zulu time for 3.5 hours from now. No need to do math in your head! Zulu Time automatically adjusts for daylight savings and your local time zone. Add a widget to your Home Screen by long pressing on your Home Screen, then tapping the "+" in the upper left corner and selecting any of the Zulu Time Widgets.
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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
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Zustand
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.
