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.
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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 Spark Mail: AI Email Assistant: map the core Productivity 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: Email management can be overwhelming with too many features
Validate with people who use this workflow before building.
Hypothesis 2
Assumption to check: Calendar views are often cluttered and hard to read
Validate with people who use this workflow before building.
Hypothesis 3
Assumption to check: Search functionality can return irrelevant results
Validate with people who use this workflow before building.
Hypothesis 4
Assumption to check: In-app purchases can be confusing or hidden
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.
Reclaim your time and focus with Spark — the AI-powered email app loved by millions. Declutter your inbox, manage your calendar, and move through emails faster than ever. “Best of the App Store” – Apple “It’s a combination of polish, simplicity, and depth.” – FastCompany “You can create an email experience that works for you.” – TechCrunch MANAGE MULTIPLE EMAIL ACCOUNTS Connect all your emails — including Gmail, Microsoft Outlook, AOL, Yahoo, Hotmail, IMAP, GMX, and iCloud — in one unified inbox. STAY ORGANIZED WITH SMART INBOX Keep personal and high-priority emails up top — newsletters and notifications stay neatly grouped below. WORK SMARTER WITH SPARK +AI Summarize long threads, draft replies, rephrase messages, and adjust tone — all powered by AI. Use your AI Assistant to manage your inbox, translate emails, and keep projects moving. GET MORE DONE WITH EMAIL ESSENTIALS - Mark emails as done or set aside for later - Mute email threads you’re no longer interested in. - Schedule emails to send later — even if your device is off. - Filter with Smart Search and Smart Folders PROTECT YOUR INBOX WITH GATEKEEPER Pre-screen new senders with Gatekeeper and block unwanted contacts instantly. PRIORITIZE EMAILS AND SENDERS Mark what’s important so it’s always at the top of your inbox. Group emails from senders or domains to keep your inbox clean. MANAGE YOUR CALENDAR AND MEETINGS Connect your calendars to stay on top of your day. CONNECT EMAILS TO INTEGRATIONS Connect Spark to apps like Notion, Asana, Things, and 10+ integrations to take action on everything in your inbox. SECURE AND PRIVATE EMAIL Spark encrypts your data, relies on Google Cloud’s secure infrastructure, and is fully GDPR compliant. COLLABORATE WITH YOUR TEAM - Create a team to collaborate on emails. - Co-author emails and discuss content in private comments. - Share secure links to specific emails. - Track read receipts to keep work moving. ENJOY THE ESSENTIALS FOR FREE Try Spark Plus or Spark Pro free for 7 days — or stick with our powerful free plan. Download Spark and reclaim your day. What is Spark? Spark is a cross-platform email client that helps individuals and teams manage their inboxes and calendar with smart, AI-powered tools. It works across all platforms and devices so that you can be more effective, at home, in the office, or on the go. Who is Spark for? Short answer: Anyone who deals with a lot of emails. Spark is perfect for busy professionals, freelancers, and teams who need to stay organized and communicate effectively. It’s also great for individuals who want to manage their personal and work accounts in a unified inbox. Is it difficult to set up? Spark is highly customizable, but also easy to master. You’ll find multiple ways to set up your inbox, swipes, and shortcuts in Settings. Terms of Service: https://sparkmailapp.com/legal/terms Privacy Policy: https://sparkmailapp.com/legal/privacy-app Help: [email protected]
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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.