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.
Practice and perform jazz standards on another level with Quartet.
$19.99 · In-app purchases
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.
A product spec, screen plans, and build steps for your coding agent.
First kit free with a verified email
Combine features and design from your favorite apps.
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Generating… usually about a minute.
What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
A product spec, phased build plan, differentiation notes, and screen references.
Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Goal: Send a clear invoice after finishing a job.
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.
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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Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
Rork plan preview for Quartet 1: 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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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
Assumption to check: Limited music discovery options compared to competitors
Validate with people who use this workflow before building.
Hypothesis 2
Assumption to check: High subscription cost may deter users
Validate with people who use this workflow before building.
Hypothesis 3
Assumption to check: Lack of offline mode for downloaded music
Validate with people who use this workflow before building.
Hypothesis 4
Assumption to check: User interface is not very engaging
Validate with people who use this workflow before building.
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
Practice and perform jazz standards on another level with Quartet. And with a host of brand-new features, the top-selling jazz play along apps just got even better. No subscriptions. No in-app purchases. Volume 1 includes 150 stunning jazz standards recorded exclusively by 7 of the world’s best jazz musicians. All ‘live’ studio recordings with intros, endings and top line solos. Whether you play jazz piano, guitar, saxophone, trumpet, bass, drums…simply mute your instrument from the Quartet for the ultimate jazz play along. And for jazz singers too, each edition of Quartet is an unrivalled collection of jazz backing tracks powerful enough to gig with. Change key on the fly. Speed up or slow down the audio seamlessly. Loop sections and slow them right down for practice. Select the number of repeats. Choose from preset mixes or create your own custom mix using the new onboard mixer. Arrange each song exactly the way you want it with the new ‘Arranger’ feature. Add a touch of reverb and you’re good to go. Improve your skills with full screen animated chord diagrams for Piano, Guitar and Ukulele. Search the entire Quartet song library (650 songs) by composer, style, BPM, associated artist and more. Build and share multi-app playlists and easily export PDF chord charts for every song. Export your stereo mix or export the multitrack if you want to develop the high quality separated parts in GarageBand or whatever DAW you use. Either way, all recordings are offered to you royalty-free giving you endless creative possibilities. The 150 jazz standards in Quartet Volume 1 include improvisations in the style of… ‘All Blues’, ‘All of Me’, ‘All The Things You Are’, ‘Autumn Leaves’, ‘Beautiful Love’, ‘Blue Bossa’, ‘Body and Soul’, ‘Caravan’, ‘Cherokee’, ‘Cry Me a River’, ‘Georgia on my Mind’, ‘Giant Steps’, ‘Girl From Ipanema’, ‘Have You Met Miss Jones?’, ‘Love for Sale’, ‘Rhythm Changes’, ‘Satin Doll’, ‘Someday My Prince Will Come’, ‘Stella By Starlight’, ‘Summertime’…and 130 more. Install Quartet on all of your iOS devices plus your Mac devices (M series only) at no extra cost. Ready to take your jazz standards to another level? Hear more at www.quartetapp.com Featured artists Saxophones and Flutes Graeme Blevins Recording and performing credits include Phil Collins, Robbie Williams, Kylie Minogue, Kyle Eastwood, Mark Knopfler, Quincy Jones, Mark Ronson, Tom Jones, Taylor Swift, Martha Reeves, The Royal Philharmonic Orchestra Andy Panayi Credits - Shirley Bassey, Jessye Norman, Paul McCartney, Seth MacFarlane, Elaine Paige, Salena Jones, Elvis Costello, Georgie Fame, Irene Reed, Elaine Delmar, Helen Shapiro, Madeline Bell, Patty Austin, Freddie Hubbard, Wynton Marsalis, Joe Lovano, Roy Hargrove Dave O’Higgins Credits - Joey Calderazzo, Joe Locke, Dave Kikoski, Eric Alexander, Grant Stewart, Max Ionata, Phil Dwyer, Adam Nussbaum, Joe Lovano, Phil Woods, Jimmy Smith, Nancy Wilson, Peggy Lee, Kurt Elling, Wayne Shorter, Eddie Gomez, Jamie Cullum, Stephane Grappelli, Michel Legrand Piano Graham Harvey Credits - Incognito (MD), Stacey Kent, George Benson, M People, Hamish Stuart, Will Lee, The Jones Girls, Philip Bailey, Chaka Khan, The BBC Big Band, Omar, Madeline Bell, Jocelyn Brown, Mica Paris, Kenny Thomas, Sir Cliff Richard Bass Geoff Gascoyne Credits - Jamie Cullum (MD), Sting, Van Morrison, Bill Bruford, Mari Wilson, Paloma Faith, Georgie Fame, Gloria Estefan, Guy Barker, Charlie Watts, Chris Standring, Everything But The Girl, Benny Golson, Jacqui Dankworth, Bob Dorough, John Martyn, Claire Martin, Eartha Kitt Drums Sebastiaan de Krom Credits - Herbie Hancock, John Scofield, Phil Woods, Dave Holland, Jamie Cullum, Guy Barker, Wynton Marsalis, Clark Terry, Tim Garland’s Big Band Rod Youngs Credits - Gil Scott-Heron, Lee Konitz, Sia, Courtney Pine, Jon Hendricks, Hugh Masekela, Natalie Cole, Mica Paris, Denys Baptiste, Juliet Roberts, BBC Concert Orchestra, Ronnie Laws, Jocelyn Brown
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Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
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.