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
Interval Timer Pro
We’re proud to introduce this handy little app that helps you keep track of your work and rest periods during workouts
$2.99 · In-app purchases
PRICE
$2.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.5
598 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 included17 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 Interval Timer Pro: map the core Health & Fitness 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
Provide templates for common workout types.
Assumption to check: Users find timers hard to customize for different workouts.
Validate with people who use this workflow before building.
Hypothesis 2
Implement more precise timing mechanisms.
Assumption to check: Some users report bugs with timer accuracy.
Validate with people who use this workflow before building.
Hypothesis 3
Add export features to connect with popular fitness platforms.
Assumption to check: Limited integration with other fitness apps.
Validate with people who use this workflow before building.
Hypothesis 4
Introduce social sharing capabilities for user progress.
Assumption to check: No social features for sharing workouts.
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
We’re proud to introduce this handy little app that helps you keep track of your work and rest periods during workouts. Whether your into cycling, running, lifting weights, exercise, workout, stretching, boxing, MMA or HIT, this interval timer will prove to be an invaluable asset to you. Running foreground, background or with device locked, this reliable app allows you specify an overall time as well as program High/Low intensity interval and rest time between sets. Key Features: - Customizable sets, high/low intensity interval and rest for your own need - Retina display, iOS4 and multitasking - Continue to run even when screen is locked - Play your song or playlist during your workout - Post your workout to Facebook or Twitter - Save settings as templates Customizable Features: - Number of Sets - Countdown Time - Set Time - Low Interval time - High Interval time - Rest Time - First Interval (low or high) - Sound Volume - Timer Sounds - Auto Lock - Vibrate - Pause during Rest - Playlist - New Each Set
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
react-navigation
@react-native-async-storage/async-storage
expo-sound
expo-haptics
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.
