MZmzitelli·Jan 7, 2026Submission
Show HN: An offline first, with state-in-URL, workout planning and tracking app
After getting frustrated with existing workout planning and tracking apps, I decided to build my own with the following requirements:
- allow tracking weight, reps, difficulty per series
- being flexible, so I have my plan, but can adapt without having to change my original plan
- it surfaces the relevant context when needed
- it adapts to my trains
- i can access it anywhere
- don't let me get distracted
- low maintenance
I decided to solve that with an app with the following user flow:
- you plan workout days with exercises in order, no weights, supersets, or anything, that will be detected and defined as you train
- when working out, you select an exercise, put the desired weight, reps, rest time, and start one set
- when done with the set, mark its difficulty
- a sound will ring when your rest time ends
- as you go, and have a history
Read the rest
of exercises, the app automatically suggests the next exercise, weights, reps, and resting time based on a few heuristics
- you can always select another exercise from the day, from another day, or even search for a completely different exercise
The app includes the entire state in the URL, so no server is required. We use the amazing https://github.com/yuhonas/free-exercise-db. Big kudos to the creators! In the end, the entire site and DB are hosted by GitHub.
The URL is from my current usage. You can view my daily plans and previous sessions there. In the plans, you can click on exercises to see suggestions based on previous sessions.
All edits you make will alter the URL and be saved in local storage. When you return to https://mateuszitelli.github.io/trainlink/, the page restores its previous state.
It has been very pleasant to use it in the last few days. Please, try it and let me know what you think. You can find the source code here: https://github.com/MateusZitelli/trainlink