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
Stopwatch for Track & Field
The professional stopwatch built for track & field.
$1.99 · In-app purchases
PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.6
337 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.
Build your own version
Build Kit
Make this idea yours
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 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 Stopwatch for Track & Field: map the core Sports 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
Add customizable features like split times and detailed statistics.
Assumption to check: Limited functionality for advanced timing features
Validate with people who use this workflow before building.
Hypothesis 2
Integrate sharing capabilities for results on social media.
Assumption to check: No social sharing options
Validate with people who use this workflow before building.
Hypothesis 3
Allow users to create profiles to save and compare their results.
Assumption to check: Lack of user profiles
Validate with people who use this workflow before building.
Hypothesis 4
Offer more features in the free version to encourage upgrades.
Assumption to check: In-app purchase limitations
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 professional stopwatch built for track & field. Trusted by coaches, parents, and athletes at every level — from high school to elite competition. Time anyone. Time everyone. Time a single athlete with full split details, or run an entire group simultaneously. Every runner tracked, every lap recorded, every estimated finish time calculated — in real time. Built for the sport. Supports 30 individual events and 13 relay distances, including hurdle events with per-hurdle split recording. The app knows your event inside out — distances, laps, and final splits are all preloaded. Smart Stop The app knows when the final lap arrives and stops automatically — whether you tap Lap or Stop. Your complete timing history Every result is saved for later review and sharing. Export detailed split reports by email or your preferred app. Team-ready Build your roster, organize athletes into teams, and import/export across devices. Built for busy meet days. Questions or feedback? Contact us at [email protected]
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
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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.
