Marathon training planner

1 month ago

I am running a marathon in October 2026 and a backyard ultra in March 2027, so I needed a way to plan my runs and train more consistently.

Back in February 2026 I just asked ChatGPT to put a training schedule together, but it kept losing the context. It was constantly wrong about what day it actually was and which workout it was supposed to update.

So I built this: a marathon training planner where you put a plan together through an interface, and at the end you hand that plan to an AI. The AI generates a full schedule for you, which you then import back into the app.

From there the app does the rest. You can easily change workouts, log what you actually ran with your pace and time, and keep an eye on a calendar and a stats overview. It even shows the weather for your training days, and you can connect your Google Drive to save your plans to the cloud.

One of my favourite features is how easy rescheduling has become. When something comes up, a festival, or in my real case a skin infection on my leg, I just export the plan and give it to the AI. Because it now has all the context of the plan, we can reshuffle the trainings in no time, so I can still finish this October with a good time.

In the meantime friends, family and colleagues have started using it too. That is pretty validating: even though I originally built it just for myself, it feels rewarding to help other people with something you made, even if it is only a small group.

The code lives on GitHub: marathon_schema.