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.
With the Bach Cantatas app you have an extensive reference of all sacral and secular vocal works of Johann Sebastian Bach
$29.99 · 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.
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Combine features and design from your favorite apps.
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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 Cantatas: map the core Reference 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 search and filtering options.
Validate with people who use this workflow before building.
Hypothesis 2
Assumption to check: High pricing for premium content.
Validate with people who use this workflow before building.
Hypothesis 3
Assumption to check: Lack of community features.
Validate with people who use this workflow before building.
Hypothesis 4
Assumption to check: Occasional audio loading issues.
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.
With the Bach Cantatas app you have an extensive reference of all sacral and secular vocal works of Johann Sebastian Bach. The app has a collection of all cantatas complete with arias, recitatives, choirs and chorales. Containing the instrumentation, text, librettists and scriptural references and interactive parody references for the individual cantata movements. With a few swipes you get all informations for a cantata at hand. Sort the cantatas for title, opus, designation, date of creation or current position in the liturgical year. Through the search field you can find cantatas for instruments, designation, movement text, librettist or even scriptural reference within seconds. Take a look at the score of the Bach Society Edition (Alte Bachausgabe), quite clearly arranged directly to each cantata. In addition, the app contains links to the autographs of bach-digital.de. Thus, you are only a fingertip away from the Bach original sources. The scores of the Bach Society Edition will be downloaded from the Internet as required. For searching bach-digital.de you also need an Internet connection. With the search catalog you find arias, sinfonias or chorals sorted by solo part oder instrumentation. Choose a predefined search from the catalog or create your own criterias with the interactive user interface. In addition, the app contains all chorales used by J.S.Bach including all verses. For even more context the app contains the entire (!) Bible in the King James translation and an interactive biblical concordance for the cantatas. It has never been easier to discover information on the use of Bible verses in Bach's cantatas. The Cantatas app comes with a complete database for all of it's content. No internet connection is required to research a cantata. It even contains the complete epistel and gospel texts for all feasts of the liturgical year, designated to each cantata.
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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.