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
VB3m
GSi VB3m simulates the famous american tonewheel organ better known as the Hammond Organ B3.
$14.99 · In-app purchases
PRICE
$14.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.5
40 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 included17 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 VB3m: 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
Expand the sound library with user-generated content and third-party integrations.
Assumption to check: Limited sound library compared to other synthesizer apps
Validate with people who use this workflow before building.
Hypothesis 2
Implement an interactive tutorial for new users to guide them through app features.
Assumption to check: No built-in tutorial or help section
Validate with people who use this workflow before building.
Hypothesis 3
Optimize audio processing and memory management for smoother performance.
Assumption to check: Performance issues with complex projects
Validate with people who use this workflow before building.
Hypothesis 4
Clarify subscription benefits and provide a better overview of in-app purchases.
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
GSi VB3m simulates the famous american tonewheel organ better known as the Hammond Organ B3. Main features: - Two manuals plus pedalboard - Two sets of 9 drawbars each for upper and lower manual - Two drawbars for the pedalboard - Physical modeling engine with full polyphony (91 tonewheels) - Rotary speaker effect with two variations plus one static amp - Virtual microphone positioning - Tube overdrive simulation - Two band equalizer - Digital reverb - Program bank with 32 memory locations - On screen keyboard (upper manual only) - Split function - Pedal-to-lower function - Pedal String Bass decay - Global tuning between A=430 Hz and A=450 Hz - Fully customizable Midi CC Mapping with Midi Learn function - Reverse all drawbar CC option - Sustain pedal support for sustaining notes - User selectable Midi channels - Freely assignable Program Change numbers - Low latency Core Audio support - IAA support - AUv3 plugin extension included - Background audio option - Free Cloud service to easily exchange Programs and Midi Maps Please note: to connect a USB-Midi controller, please use Apple's Camera Connection Kit (Lightning to USB-A). Don't connect your recharge cable to a USB host port, that won't transfer Midi data. For better performance, make sure your battery is fully charged or power your device wherever possible. For more details, please read this Q&A article: https://lnx.gsidsp.com/help/knowledgebase.php?article=1
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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.
SUGGESTED BUILD STACK
Expo AV
React Navigation
Zustand
React Native Gesture Handler
React Native Reanimated
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.
