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
CalStack
CalStack is a personal command center for your calendar, email, tasks, notes, contacts, and AI assistant.
$4.99 · In-app purchases
PRICE
$4.99
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.
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 included15 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 CalStack: map the core Productivity 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
Implement AI suggestions for task prioritization based on deadlines and user behavior.
Assumption to check: Users often struggle with task overload and prioritization.
Validate with people who use this workflow before building.
Hypothesis 2
Introduce shared projects and task assignments.
Assumption to check: Lack of collaboration features can hinder team productivity.
Validate with people who use this workflow before building.
Hypothesis 3
Enhance cloud sync capabilities and offline access.
Assumption to check: Difficulties in syncing tasks across devices.
Validate with people who use this workflow before building.
Hypothesis 4
Allow users to customize themes and notification settings.
Assumption to check: Limited customization for user preferences.
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
CalStack is a personal command center for your calendar, email, tasks, notes, contacts, and AI assistant. Built for people who live across meetings, travel, family schedules, projects, and inboxes, CalStack brings the day into one focused view instead of scattering it across apps. See your day, upcoming week, pinned events, meetings, reminders, and time zones in a single dashboard. Use Start Day, Check In, and Wind Down rituals to turn your calendar, email, tasks, and notes into practical daily context. CalStack also includes an AI chatbot that can work with your local app context, including calendar events, synced notes, processed email, contacts, and saved preferences. You can connect supported AI providers or local model servers depending on your setup. Key features: • Unified calendar dashboard • Day, week, month, quarter, year, and list calendar views • Pinned and starred calendar events • Time zone dashboard with time scrubber • AI-assisted Start Day, Check In, and Wind Down workflows • Email sync and searchable email context • Brain notes and memory layer • Contact tracking • Meeting and video link support • Local model support for privacy-focused workflows • iCloud sync for supported app data • Native iPhone, iPad, and Mac layouts CalStack is designed to help you understand what matters today, prepare for what is coming next, and keep useful context close without turning your day into another inbox.
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
Zustand
react-navigation
@react-native-community/datetimepicker
expo-secure-store
BUILD KIT DIFFICULTY
Intermediate
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.
