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
Elastic Drums
Machinedrum: "It's awesome, a lot of fun to work with and very easy to get something going
$9.99 · In-app purchases
PRICE
$9.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.6
145 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.
Build your own version
Build Kit
Make this idea yours
A product spec, screen plans, and build steps for your coding agent.
First kit free with a verified email
Add to a Remix
Combine features and design from your favorite apps.
Kit ready. Verify your email to download it.
Generating… usually about a minute.
Make it yours Optional
What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
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/
Preview a sample Build Kit No email needed
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.
JavaScript is required to complete mailbox verification.
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 Elastic Drums: map the core Music workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
Preview ready. Verify your email to reveal and copy the full prompt.
JavaScript is required to complete mailbox verification. Return to this prompt preview.
Continue in Rork >
Affiliate link: CloneChart may earn a commission at no extra cost
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
Offer more sound editing features and effects.
Assumption to check: Limited sound customization options.
Validate with people who use this workflow before building.
Hypothesis 2
Implement guided tutorials and onboarding.
Assumption to check: Steep learning curve for beginners.
Validate with people who use this workflow before building.
Hypothesis 3
Provide clear information about what each purchase unlocks.
Assumption to check: In-app purchases can be unclear.
Validate with people who use this workflow before building.
Hypothesis 4
Optimize performance for larger projects and audio files.
Assumption to check: Performance issues with large projects.
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
Machinedrum: "It's awesome, a lot of fun to work with and very easy to get something going. I love the sound presets too.“ Keyboards: „An extremely flexible beatbox with tons of character." CDM: "Finally, Your Pocket Gets a Perfect Drum Synth: Elastic Drums for iPhone." FACT Magazine: „One of the iPad’s best drum machines.“ Unlike most drum apps that rely heavily on samples, Elastic Drums uses drum synthesis models - making the sounds much more elastic and deeply tweakable. This approach allows for radical sound shaping, and when combined with the app’s versatile effects section, Elastic Drums becomes not just a beat-making tool, but a powerful instrument for sound design. Features: - 6 synth channels with 20 different percussion synth engines (kick, snare, hihat, clap, tom, wobble, fm, fm4, square, grain, synth, drone, sampler, 808 kit) - 12 parameters for each synth engine - Automation for each parameter via knob recording or velocity - 4 send effect channels with 2x13 mono effects and 2x11 stereo effects - Automation for all of the 8 possible effect parameters via xy pad - Master effects (stutter, delay, compressor ...) - 16 step sequencer for the 6 channels, each with it's own tempo multiplier & length - Record audio and export to via Airdrop or Audioshare - Email audio recordings and presets - Ableton Link synchronization and Ableton Live Set Export - Audiobus, Audiobus Remote, Inter-App Audio - Midi learn/Midi implementation of the most important parameters Factory presets by: App Sound, Ben Jeffrey, Bill Jobs, Dead Fader, Hecq, Kero, Leonard de Leonard, Machine Drum, Mouse on Mars, Ochre, Pan, Phlex, Pilocka Krach, Red Sky Lullaby, Servando, Shadow Dancer, Swarm Intelligence, zNo
Written user reviews are not shown here. Check current App Store reviews >
Screenshots
< Scroll to see more >
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
Redux
React Navigation
Axios
Lottie for animations
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.
