Thanks for your answer. I already watched your video that helped me to get the view (by the way you helped so much with your tutorials, thanks a lot). But the goal is to display data from an external API without modifying possibility. 

So the solution I came with is : 

1 - I create the fields in my model 

2 - I create a controler that makes the API external calls

3 - I create a javascript class that fetch the controler, and display the data on the field in the view through widget.

That would seem ok for you ? It seems to work but I don't know if it's a good solution.

Thanks 

Hi,

If you need to add the newly added fields in to your view, you can inherit the view and XPath and add the fields in to the arch.You can refer to the below video:

https://www.youtube.com/watch?v=eqpmeOrOSgI

Hope it helps