Proximity filter & exposed or contextual

Hi,

I am trying to limit json results based on radius from search or geolocated position.
It's possible to use geofield proximity in geojson views with bbox argument?

Adding in contextual filters default value for proximity geofield (bbox argument)
Adding in filter geofield proximity with source of contextual filter geofield proximity
Sorting results based on proximity?

Or it's better to adjust from google store javascript those changes?