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.
The Most Reliable Penalty Timer for Roller Derby Officials
$3.99 · In-app purchases
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.
A product spec, screen plans, and build steps for your coding agent.
First kit free with a verified email
Combine features and design from your favorite apps.
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Generating… usually about a minute.
What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
A product spec, phased build plan, differentiation notes, and screen references.
Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Goal: Send a clear invoice after finishing a job.
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.
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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Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
Rork plan preview for Penalty Timer - Roller Derby: 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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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
Assumption to check: Poor user interface and user experience.
Validate with people who use this workflow before building.
Hypothesis 2
Assumption to check: Limited functionality for tracking multiple penalties.
Validate with people who use this workflow before building.
Hypothesis 3
Assumption to check: Lack of customization options.
Validate with people who use this workflow before building.
Hypothesis 4
Assumption to check: No support for game statistics tracking.
Validate with people who use this workflow before building.
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
The Most Reliable Penalty Timer for Roller Derby Officials Finally, a penalty timer built specifically for roller derby that actually works when you need it most. Whether you're a referee managing a chaotic jam or a coach running practice with limited staff, PenaltyTimer delivers precision timing with built-in WFTDA knowledge. - WFTDA COMPLIANT & RULE-SMART All penalty codes built-in (BC, FE, HB, LB, MP, IC, II, IP) Automatic 30-second durations with double-penalty support Handles tricky jammer situations according to official rules 10-second warning alerts - never miss telling skaters to stand - BUILT FOR REAL DERBY CONDITIONS Works 100% offline - no wifi crashes during crucial moments Lightning-fast tap-edit for quick time adjustments Stop ALL timers simultaneously between jams with one tap Customizable team colors to match any bout setup - FLEXIBLE FOR ANY SITUATION Two Blockers: Perfect for scrimmage or short-staffed practice Two Jammers: Ideal for jammer-focused drills Four Blockers: Standard penalty box management Full Penalty Box: Complete 6-skater capacity for regulation bouts - DESIGNED BY DERBY PEOPLE, FOR DERBY PEOPLE Unlike generic stopwatch apps that fail under pressure, PenaltyTimer was designed specifically for the unique needs of roller derby officials. Every feature solves a real problem we've all experienced. - KEY FEATURES: Reliable timing that won't crash mid-jam Visual and vibration warnings at 10 seconds One-touch penalty serving and timer management Team color customization for easy identification Penalty history tracking for post-bout analysis No accounts, no ads, no internet required - PERFECT FOR: WFTDA/MRDA certified referees Coaches running practice sessions League training officials NSOs managing penalty tracking Anyone tired of unreliable timing apps - ZERO HASSLE SETUP Download, open, and start timing penalties immediately. No registration, no cloud sync, no complicated setup. Just reliable derby timing when you need it. - BATTLE-TESTED RELIABILITY Built to handle the intensity of roller derby. No more app crashes during power jams, no more lost penalty times, no more fumbling with complex interfaces while trying to manage the box. Stop fighting with inadequate timing tools. Get the penalty timer that understands roller derby as well as you do. Perfect for WFTDA, MRDA, JRDA, and recreational leagues worldwide.
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Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
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.