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
TREBEL Music - Download Songs
TREBEL Music is a free music app that allows you to listen to your favorite music offline, on-demand, and anytime!
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.7
185,859 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 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 TREBEL Music - Download Songs: 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 music library through partnerships with music labels.
Assumption to check: Limited song library compared to paid competitors.
Validate with people who use this workflow before building.
Hypothesis 2
Offer ad-free subscription tier.
Assumption to check: Occasional ads interrupt user experience.
Validate with people who use this workflow before building.
Hypothesis 3
Improve download speed with better server infrastructure.
Assumption to check: Downloading songs can be slow or fail occasionally.
Validate with people who use this workflow before building.
Hypothesis 4
Simplify the layout and enhance navigation for better usability.
Assumption to check: User interface feels cluttered and can be confusing.
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
TREBEL Music is a free music app that allows you to listen to your favorite music offline, on-demand, and anytime! Search for your favorite track, artist or album; alternatively, browse curated playlists from our team. Download the music you want, make and share playlists, and listen whenever without limits. Choose from new releases or all-time favorites, music for your every mood: Hip Hop, Pop, EDM, Rap, Country, Latin, R&B, Reggaeton and more. iOS 14.0 or GREATER REQUIRED. Key TREBEL Music features: • Play offline (no data or Wi-Fi connection needed after downloading music) • Listen on-demand with unlimited skips: choose the songs you want to play • Listen off-screen: lock your screen or multitask while listening • Song ID: identify the song playing around you with just one tap • Unlimited music downloads enabled by caching technology Please send questions to: [email protected] Like the app? Rate us 5 stars and hit us up on Instagram @trebelmusic --- Downloading free music on TREBEL is as easy as tapping a button. No more stream-ripping YouTube videos or wasting time on old school torrent sites to get the music you love. We’re working hard to get more free music content for offline play, so keep checking back if you can’t find the song you want. TREBEL is a licensed service with the best music in the world from Universal Music Group, Warner Music Group, Sony Music, and The Orchard. HIT US UP BELOW! Instagram: @trebelmusic Reddit: r/Trebel Twitter: @trebelmusic Facebook: @trebelapp www.trebel.io Terms of service & privacy policy: https://trebel.io/policy/terms https://trebel.io/policy/privacy
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
Expert
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.
