Build a Caffeine and Sleep Correlation Tracker

1. 1

   Make logging nearly effortless

   The product dies if logging a coffee takes more than three seconds. Preload common drinks with published typical caffeine ranges, remember favorites, and support a one-tap repeat. Honest uncertainty is fine: a range per drink beats false precision, and the correlations still emerge.

2. 2

   Read sleep, never guess it

   Pull sleep duration and quality signals from the phone and watch health frameworks with explicit permission rather than building your own sleep detection. You are the analysis layer between two data sources that already exist; keep the scope that small on purpose.

3. 3

   Show each person their own pattern

   After two weeks, the payoff view: your sleep on days with caffeine after 2pm versus before, your average with three-plus drinks versus one. Personal data beats generic advice because caffeine clearance genuinely differs between people; the app's honesty is that it never claims your neighbor's cutoff is yours.

4. 4

   Stay on the wellness side of the line

   No insomnia diagnosis, no treatment claims, no medical language. Frame everything as personal pattern observation and suggest a clinician for real sleep problems. This keeps the app in the wellness category app stores and regulators treat gently, and it is also just true.

5. 5

   Price simply and respect privacy loudly

   A modest one-time unlock or small annual subscription fits a single-purpose tool. Health-adjacent data demands a plain privacy stance: processed on device where feasible, never sold, deletable in one tap. Make that a marketing point, because your audience reads privacy labels.

6. 6

   Launch where sleep-curious people gather

   Sleep and caffeine subreddits, quantified-self communities, and wellness newsletters respond to a well-made personal-data story. Publishing anonymized aggregate findings (average personal cutoff across users) makes shareable content that markets the app without health claims.

Do not take our word for the money. Put your own numbers in and see what this idea has to earn before it works. Free, instant, no account needed.