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
PitchLab - Baseball & Softball
PitchLab turns your iPhone into a professional-grade pitch tracking system, no extra hardware required
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.7
2,048 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 included16 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 PitchLab - Baseball & Softball: 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
Expand drill library and user-generated content.
Assumption to check: Limited drill variety compared to competitors
Validate with people who use this workflow before building.
Hypothesis 2
Incorporate AI-driven training recommendations.
Assumption to check: Lack of personalized training plans
Validate with people who use this workflow before building.
Hypothesis 3
Implement more detailed analytics and tracking features.
Assumption to check: Difficult to track progress over time
Validate with people who use this workflow before building.
Hypothesis 4
Simplify subscription options and clarify premium features.
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
PitchLab turns your iPhone into a professional-grade pitch tracking system, no extra hardware required. Improve your pitching instantly with data. Break down your bullpen sessions, see pitch-by-pitch analysis, and get pro-level metrics. Built by AI/Computer Vision expert Dr. Brian Martin and MLB player Jake Fishman, PitchLab delivers professional-grade pitch data using a single iPhone camera that has competitive accuracy to radar based technology. Core Features • Track Pitch Velocity – Get precise readings without a radar gun. • Measure Vertical & Horizontal Break – Understand exactly how your pitches move. • Active Spin & Spin Axis – See how the spin of your throw affects the movement. • Automatically Trim Video – We automatically detect every throw and trim the video around it. • Real Time - Our algorithm operates in real time, giving you results immediately after you throw • Tracer Overlay - We automatically add a tracer overlay to clearly show how the ball moves • Export Sessions - Export your entire session as one video for easily playback and sharing • Session Review – Swipe through the video feed to watch back your bullpen. • Performance Tracking – Monitor progress over time and set measurable goals. INDIVIDUALS Use PitchLab to track velocity, movement, and spin in real time. Review video of every pitch, share highlights on social media, and get the insights you need to improve your arsenal. COACHES & FACILITIES Automatically track your players’ pitch metrics and video. Analyze trends over time to objectively pinpoint areas for improvement. Automatically see video and data from clients training remotely. Ability to create more pitcher profiles and track data for each pitcher you coach. Backed by Pros Never before have pitchers been able to get advanced analytics without spending thousands on radar-based hardware. With PitchLab, every player can get the data that has shaped so many big-league careers, anywhere they train. Privacy Policy: https://pitchlab.app/privacy Terms of Service: https://pitchlab.app/terms
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.
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BUILD KIT DIFFICULTY
Advanced
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.
