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
LE04 | AR-909 Drum Machine
Inspired by dusty old circuits from 1983..
$2.99 · In-app purchases
PRICE
$2.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.8
1,508 ratings · Top 5%
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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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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Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for LE04 | AR-909 Drum Machine: 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
Enhance with more diverse drum sounds and sample packs.
Assumption to check: Limited sound library compared to competitors
Validate with people who use this workflow before building.
Hypothesis 2
Allow exporting patterns as audio files.
Assumption to check: No export options for patterns
Validate with people who use this workflow before building.
Hypothesis 3
Implement guided tutorials and tips within the app.
Assumption to check: Steep learning curve for beginners
Validate with people who use this workflow before building.
Hypothesis 4
Add features to share patterns on social media.
Assumption to check: Lacks social sharing features
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
Inspired by dusty old circuits from 1983... Sounds Analog and Alive. Create your own sound. Your own beat. Your own vibe. This app is inspired by a specific piece of drum machine hardware. "The AudioKit 909 is PERFECT, fantastic job!" - Jakob Haq, iOS YouTuber "Very cool..I really like the vibe of it!" – J Miles, Grammy-winning producer (Michael Jackson) + Hybrid Synth/sample based drum creation + AUv3 (Use as plugin in GarageBand, AUM, Cubasis 3, BM3, etc) + Easy to use controls. Create your own sound. Live tweaks. + Exclusive special sauce. Vibe it out. + Ableton Link if you want to rock it standalone Tweak the knobs. This is a drum machine that is meant to be PLAYED. Switch Patterns on screen (or with MIDI) to create new creations on the fly for live performance or songwriting. It's like getting an expensive piece of vintage hardware on your iPhone and iPad. Small & mighty: Entire app less than 20mb (on most devices) WEBSITE: audiokitpro.com/analog909 REQUIREMENTS: iPhone 6s and above screen size. Requires iOS 11 and above. Will not work with 1st generation SE phones. MIDI Guide: + MIDI for drum triggers (Bass Drum, Snare, etc) start on "C" Note 36 (C1 in GarageBand) + MIDI for pattern triggers start on "C" Note 12 (C-1 in GarageBand) COMING: + AUv3 automation coming to AUM + MIDI CC and MIDI Learn coming + Better AUv3 timing coming. For now, try lowering buffer for quicker latency + MIDI Out This app is part of our Limited Edition App Series: https://audiokitpro.com/appdrops Thank you for your support. Looking forward to hearing your creations, please tag @audiokitpro on Instagram and Twitter :) NOTE: This app has no affiliation with Roland. It is a brand new synth drum machine for your enjoyment.
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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
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.
