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
Kujun
See your consistency at a glance — and keep it completely to yourself.
$0.99 · In-app purchases
PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
N/A
No ratings yet
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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Build Kit
Make this idea yours
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.
What's included16 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.
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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 Kujun: 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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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
Implement advanced filtering and sorting features.
Assumption to check: Difficulty in managing large task lists effectively.
Validate with people who use this workflow before building.
Hypothesis 2
Provide seamless cloud sync and backup.
Assumption to check: Lack of cloud sync options for task management.
Validate with people who use this workflow before building.
Hypothesis 3
Offer customizable notification options.
Assumption to check: Limited notification settings for reminders.
Validate with people who use this workflow before building.
Hypothesis 4
Add support for creating recurring tasks easily.
Assumption to check: No recurring tasks feature available.
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
See your consistency at a glance — and keep it completely to yourself. Kujun is a private, fully native habit tracker. No account. No subscription. No cloud. Everything lives on your device, and the app collects zero data. Named after the Korean word 꾸준 (kkujun) — "steady, consistent" — Kujun is built around one idea: show up daily, and watch that consistency build. PRIVATE BY DESIGN • No account or sign-up — open the app and start • No subscription required • All your data stays in a local database on your device • No analytics, no tracking, no third-party SDKs YOUR CONSISTENCY AT A GLANCE • A GitHub-style heat map for every habit • Current streak, best streak, and completion rate • The longer you show up, the better it looks CHECK OFF WITHOUT OPENING THE APP • Home Screen widgets (small and medium) show your last 7–14 days and streaks • Complete habits straight from reminder notifications • Tap the widget to jump right into the app MADE FOR DAILY USE • Create habits with a name, icon, color, and weekly schedule — daily or any set of weekdays • Sort, reorder, and edit habits any time • Gentle reminders at the time you choose • Haptics and a small celebration when your day is complete FAST AND NATIVE • Built with native iOS components, SF Symbols, and modern iOS design • Light and dark mode, at home on your iPhone YOUR DATA IS YOURS • Export a backup file any time and restore it on any device • Delete the app and nothing lingers on a server — because there is no server Start small. Stay steady. Watch the heat build.
Written user reviews are not shown here. Check current App Store reviews >
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.
SUGGESTED BUILD STACK
React Native
Expo
Zustand
React Navigation
React Native Paper
Supabase
BUILD KIT DIFFICULTY
Starter
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.
