Special characters in JSON file - not readable

Thanks for stopping by 🙂

I have a JSON file with which I control different languages. In many languages special characters are used: äöüéô and so on

As soon as I insert even one special character in my json file, it becomes completely unreadable (regardless of whether this part is read or not).

If I remove the special character, everything works again.

In older posts (2017) this was once recorded as a bug: LINK 

Is this still a bug and is there another work-around than manually inserting the code for each special character?
For example, “\u00e4” for each “ä”?

That would be quite a mess...

Thank you very much 🙂