JohnKompot Symptom Tracker

What it does

JohnKompot is a personal health symptom tracker built for HealthHack48 2026.

Appointments are short, and patients often struggle to remember what happened and when: how bad a headache was, how long it lasted, what came before it. Doctors rely on exactly those details to spot patterns and decide what to investigate. JohnKompot gives patients a simple way to build that record as symptoms happen, so they can bring an accurate history to a consultation instead of relying on memory.

A user logs each symptom with a severity rating, duration and free-text notes. The notes are where the context goes: triggers, what they were doing, anything else they noticed, or whatever else they think a doctor might want to know. Entries can then be reviewed on a calendar by date range or by symptom name, making it easy to see how a symptom changes over time and how often it recurs.

JohnKompot is a tool for recording and reviewing symptoms. It does not diagnose conditions or give medical advice.

How we built it

The project is split into two parts:

A Spring Boot REST API in Java, persisting to JSON files on disk rather than a database, to keep the setup dependency-free for a hackathon. A Flutter client in Dart, using Provider for state management and table_calendar for the calendar view.

Storing to flat JSON was a deliberate trade-off: no database to install or configure, at the cost of scalability and crash safety. The repository layer is isolated so it can be swapped for Spring Data JPA later without touching the services above it.

Challenges we ran into

We only managed to start our project properly on the second day of the hackathon, creating a real time crunch to get it done, due to this our product isn't fully intergraded. We assigned roles and split off quickly, allowing us to get large amounts of the project done but often with inconsistencies that stopped the project all coming together in the end.

Accomplishments that we're proud of

Many of our frameworks we were building around were brand new to us, making us all very proud of how much we managed to pick up of them during this single day rush. Being our first time using Dart, Flutter, and many parts of SpringBoot.

What we learned

Firstly, the most obvious learning is to start a short hackathon as soon as it starts, and not a moment after. But technically we have learnt a lot too, as aforementioned we have learnt a great deal about the frameworks we were using and are likely to use them again now we have some experience with them.

Another essential learning is to first layout a skeleton before splitting up work, so everyone knows what needs to be returned and all parts integrate nicely with each other.

What's next for JohnKompot Symptom Tracker

We will work to complete JohnKompot in our own time in order to have a finished and intergrated product. Then may even go on to making improvements: as we developed we had many extra ideas to improve the app that just couldn't come to fruition in time. Or even we're made on one side of the stack but couldn't quite be completed on the other - some of these are still comments in the code. These would be good places to start.