Thank you all,
This seems to be working now so I have just published this tool to: https://proxyformatter.herokuapp.com/
To use it, you just need to pass the destination URL after „/format/“, for example:
https://proxyformatter.herokuapp.com/format/https://sampleapis.com/countries/
Of course this only accomplishes my personal issues and almost non error handling, but can be improved if needed.
Regards!