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
Voice Builder
--RANKED IN TOP 100 MUSIC APPS WORLDWIDE!*--
$4.99 · In-app purchases
PRICE
$4.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.5
115 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 included15 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 Voice Builder: map the core Music 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
Introduce daily challenges and community-driven exercises.
Assumption to check: Limited exercise variety leading to user boredom
Validate with people who use this workflow before building.
Hypothesis 2
Incorporate AI feedback on recordings.
Assumption to check: Lack of personalized feedback on user performance
Validate with people who use this workflow before building.
Hypothesis 3
Enhance progress tracking with detailed analytics.
Assumption to check: Difficult to track long-term progress effectively
Validate with people who use this workflow before building.
Hypothesis 4
Offer more flexible pricing options and a freemium model.
Assumption to check: High subscription cost compared to competitors
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
--RANKED IN TOP 100 MUSIC APPS WORLDWIDE!*-- Voice Builder™ is a breakthrough iOS application for bringing power, resonance, range, flexibility, and endurance to the singing or speaking voice. It is the only application of its kind to be based on The Catona Voice Building System™, the revolutionary vocal exercise program for developing the muscles of the human voice. The Catona Voice Building System is the brainchild of renowned voice builder Gary Catona, who has trained many of today’s most successful singers and entertainers, including: - Whitney Houston - Andrea Bocelli - Babyface - Sade - Seal - Usher - Shakira - Lenny Kravitz - Tony Bennett - Lionel Ritchie - And many others KEY FEATURES: - Neutral Tone Technology™: Instead of vocalizing to a pre-recorded human voice (and its imperfections), you instead vocalize to a tone that is always in perfect pitch. - Voice-building exercises play automatically with a simple touch of a button. - Volume & pitch guides provide an effective visual aid in performing voice-building exercises in the correct pitch and volume. - Over 20 voice-building sessions for both male and female singers and speakers. A setup wizard makes choosing the right voice-building session quick & easy. - Gary Catona guides you every step of the way with audio commands and numerous video demonstrations. - A short video tutorial gets you up to speed quickly on both The Catona Voice Building System and the Voice Builder application. Long considered a well-guarded secret in the entertainment industry, Voice Builder now makes the Catona Voice Building System available to the world by means of an elegant, innovative, and intuitive application which is a pleasure to use, whether it be at home or on-the-go. To learn more about Gary Catona and The Catona Voice Building System, visit www.garycatona.com. *on 7/25/12
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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
Intermediate
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.
