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
Sauner - Sauna Tracker & Log
Sauner is the ultimate companion for sauna enthusiasts
$0.99 · In-app purchases
PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.7
7 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.
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Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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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 included17 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
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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 Sauner - Sauna Tracker & Log: 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.
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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
Include detailed analytics and session comparisons.
Assumption to check: Limited logging features compared to other fitness apps
Validate with people who use this workflow before building.
Hypothesis 2
Add social features for users to connect and share experiences.
Assumption to check: No community features for sharing progress
Validate with people who use this workflow before building.
Hypothesis 3
Implement customizable reminders and notifications.
Assumption to check: Lack of reminders for sauna sessions
Validate with people who use this workflow before building.
Hypothesis 4
Integrate with HealthKit or Google Fit for better tracking.
Assumption to check: No integration with health tracking apps
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
Sauner is the ultimate companion for sauna enthusiasts. Track every aspect of your sauna experience and discover your perfect wellness routine. Complete Session Tracking Record your sauna rounds including heat sessions, cold water baths, and rest periods. Track duration for each phase and monitor your progress over time. Apple Watch Integration Connect your Apple Watch to monitor heart rate in real-time during your sauna sessions. Get alerts when you reach your target heart rate. Totonoi Score Discover your personal wellness score based on your session patterns, heart rate data, and rest periods. The Totonoi score helps you understand and optimize your sauna routine. Session History and Statistics View your complete sauna history with detailed statistics. Track weekly activity, monthly trends, and personal records. Multi-Round Support Traditional sauna bathing involves multiple rounds. Sauner supports unlimited rounds per session with individual tracking for each phase. Beautiful Dashboard See your sauna journey at a glance with an intuitive dashboard showing recent sessions, streaks, and activity charts. Start your mindful sauna practice today with Sauner. Term（EULA）: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://sauna-tracker.stack-works.dev/privacy
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
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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.
