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
Vocal Pitch Monitor
It is an application which displays the pitch of the sound inputted from the microphone on a graph in real time.
$1.99 · In-app purchases
PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 2.6
42 ratings · Below Average
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 included18 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 Vocal Pitch Monitor: 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
Add features like pitch comparison and vocal exercises.
Assumption to check: Limited functionality compared to other pitch monitoring apps
Validate with people who use this workflow before building.
Hypothesis 2
Optimize app performance for a wider range of devices.
Assumption to check: Inconsistent performance on older devices
Validate with people who use this workflow before building.
Hypothesis 3
Implement intuitive onboarding and tutorials.
Assumption to check: Unclear user instructions
Validate with people who use this workflow before building.
Hypothesis 4
Focus on quality assurance and user feedback integration.
Assumption to check: Low rating due to bugs
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
It is an application which displays the pitch of the sound inputted from the microphone on a graph in real time. A horizontal axis becomes time and the vertical axis has become a scale. [Feature] - Display the pitch inputted from the microphone in real time. - Display 7 octaves from C1 to B7. - Scroll the display range automatically. - Display the present scale on the upper part of a screen in written form. - Correspond to horizontal rotation of a screen. - Recording and playback - Save/Load function - Scale setting - Color settings for each note - Tuner function [Usage] Please input a sound from a microphone. A pitch is displayed in real time. [Pitch detection] When two or more musical instruments and chords are included in a sound, it cannot analyze correctly. [Recording and playback] Only 5 minutes you can record.
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
React Native
Expo
react-native-chart-kit
expo-av
@react-navigation/native
axios
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.
