App Overview

Zulu Time icon

Zulu Time

Derek Spears · Utilities

An iPhone, Apple Watch and iPad app to see Local and Zulu time (GMT) or multiple time zones in a single glance

$0.99 · In-app purchases

PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.8
2,595 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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A product spec, screen plans, and build steps for your coding agent.

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What's included18 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.

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.

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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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Zulu Time: 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

Allow users to add custom time zones.

Assumption to check: Limited customization options for time zones

Validate with people who use this workflow before building.

Hypothesis 2

Implement offline mode for previously fetched times.

Assumption to check: No offline functionality

Validate with people who use this workflow before building.

Hypothesis 3

Create an onboarding tutorial to guide new users.

Assumption to check: Lack of a user-friendly onboarding process

Validate with people who use this workflow before building.

Hypothesis 4

Clarify purchase benefits and provide a better trial experience.

Assumption to check: In-app purchase confusion

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

An iPhone, Apple Watch and iPad app to see Local and Zulu time (GMT) or multiple time zones in a single glance. Includes Widgets for both the iPhone and Apple Watch. Useful for pilots in getting weather briefings and filing flight plans, or Ham radio operators to do timezone conversions. No more worrying about getting the timezone offset correct or Daylight Savings Time conversions. Easily convert from different time zones, including times in the future or past. On the iPhone: - Home and Lock Screen widgets - The Zulu Time page gives a quick view of both Zulu and Local times - The Offset Time page allows you to see Zulu and local time either in the future or past by entering an offset via the Offset button. Tapping either Zulu or Local times will allow you to enter a time in the future or past, synchronizing both Local and Zulu times with that offset. The offset only applies to this view (except on the iPad the offset applies to everything on the page) - The Multiple Zones page allows you to add as many time zones as you wish in a scrolling view. Clicking on any Time Zone will allow you to change it. on iPad: All information is combined on one screen. You have user customizable time zones on the right hand side. On the left, you have Zulu and Local time and one customizable time zone. The offset to see future or past time can be done via the Offset button or tapping any of either the Zulu, Local or Custom time buttons on the left. On the Watch: Complications available in all watch faces making for glanceable ZuluTime and access to the app, which gives offset able time computation.

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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.

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BUILD KIT DIFFICULTY
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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.