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
Chrono: Time in Place
Track every day you spend in every state and country — automatically.
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.6
17 ratings · Top 15%
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 included18 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 Chrono: Time in Place: map the core Finance 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 a bulk-edit feature for locations.
Assumption to check: Users find it difficult to manage multiple locations effectively.
Validate with people who use this workflow before building.
Hypothesis 2
Add detailed reports and trends.
Assumption to check: Lack of advanced analytics for time tracking.
Validate with people who use this workflow before building.
Hypothesis 3
Standardize UI components and styles.
Assumption to check: Inconsistent user interface across different screens.
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
Track every day you spend in every state and country — automatically. Recognized by Bloomberg News. Trusted by cross-border professionals and their tax advisors. Verified Presence: every location biometrically confirmed, not just GPS-guessed. Proof, not estimates. What Chrono does • Track all 50 US state residencies — 183-day rule built in • Schengen 90/180, tracked automatically — never overstay • Custom goals for any visa, residency, or tax threshold • Reports ready for your CPA or tax advisor • Private by design — data stays yours Built for people whose tax status depends on where they actually are High earners splitting time between New York and Florida. International travelers tracking Schengen 90/180 days. Cross-border professionals whose residency status drives their tax bill. "My work is project based and I travel often. This app is key for me at the end of each tax year so I don't have to remember where I was, when, or for how long. Saves me a lot of headaches and my accountant agrees!" — Chrono user Subscription Chrono offers a 14-day free trial, then a subscription that works out to less than $10/month. Cancel anytime. Auto-renewal can be managed or turned off in your Apple ID settings. Privacy Policy: https://www.gochrono.io/privacy-policy Support: https://www.gochrono.io/contact
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
@supabase/supabase-js
react-native-chart-kit
react-navigation
zustand
BUILD KIT DIFFICULTY
Advanced
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.
