Hello! I have some workouts in my account that are badly formatted. I downloaded them as JSON, applied the required fix (in a program coded by me because it is more than 600 workouts), and now, I want to import them again as JSON.
I’m not able to 
Is there any way to convert json to FIT?
If your workouts come from Polar try
No. I have my workouts in intervals. I downloaded it as JSON, applied the fix, and saved it as JSON. Now, I just wanted to import them.
Just an idea and I don’t even know if it’ll work but could you import to Golden Cheetah and then export from there as .fit
I believe that this is only supported through the API.
There are a couple of examples on that thread on how to create a workout. I’d start by looking at the POST /api/v1/athlete/{id}/workouts endpoint.