I built an app to answer one simple question: How much caffeine is still in my body?

I'm a solo iOS developer and coffee lover.

The idea for Caffy came from a simple frustration: every caffeine tracker I tried only counted how many cups I'd had. None of them answered the question I actually cared about:

How much caffeine is still active in my body right now?

So I spent months researching caffeine pharmacokinetics and built Caffy.

Instead of simply logging drinks, it estimates your remaining caffeine level throughout the day using personalized half-life models based on factors like age, gender and caffeine sensitivity.

It also estimates how today's coffee might affect tonight's sleep and includes features like a Sleep Readiness Score, a "What if I drink this?" simulator, AI Weekly Analysis and Home & Lock Screen widgets.

The app is now live on the App Store.

I'm still improving it every week, so I'd genuinely love feedback from fellow indie makers. If you have ideas, criticism or feature requests, I'd love to hear them.

Thanks for reading! ☕🚀