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
PolyTune
It's the most powerful tool you've ever had in your pants! You know ..
$4.99 · In-app purchases
PRICE
$4.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 2.8
79 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 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 PolyTune: 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 to include more string and wind instruments.
Assumption to check: Limited instrument types supported
Validate with people who use this workflow before building.
Hypothesis 2
Implement noise cancellation features.
Assumption to check: Inaccurate tuning in noisy environments
Validate with people who use this workflow before building.
Hypothesis 3
Add social sharing or tutorial sections.
Assumption to check: Lack of user engagement features
Validate with people who use this workflow before building.
Hypothesis 4
Focus on UX improvements and user feedback integration.
Assumption to check: Low app rating suggests usability issues
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's the most powerful tool you've ever had in your pants! You know ... for tuning. That said, this is one of those nuggets on the App store you cannot afford to miss if you value being in tune and you take your smartphone with you when you go places. Yes to both? Then it's a no-brainer! - Tune all strings at once! Just strum your guitar, and see the pitch of all strings instantly. - Guitar/bass mode - Drop-tunings - 1:1 port of the award-winning PolyTune pedal (Guitar Player, Guitar World, Premier Guitar, MIPA, NAMM Best in Show 2010, etc.) - Based one the world’s best selling pedal tuner used by countless pros such as Steve Vai, John Petrucci, Steve Morse, Orianthi and many more! PolyTune is the world's first polyphonic tuner that will have future guitarists wondering how we ever got by without it. The magic lies in a never before seen approach to tuning aimed at speed, accuracy and ease of use, which allows you to get in tune fast, and back to doing what you love: playing. The PolyTune iPhone app is a 1:1 port of the award-winning PolyTune pedal tuner, and PolyTune for iPhone delivers exactly the same features and tuning technology as the pedal version. The pedal version is the fastest way to tune on-stage, whereas the iPhone app is the fastest and most convenient way to tune off-stage. Specifications: - Reference pitch from 435Hz to 445Hz - Drop tuning from E-flat to B - 0.5 cent accuracy - 2 chromatic tuning modes: Needle and Stream - MonoPoly recognizes whether one or several strings are played at once
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
Zustand
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expo-av
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.
