How to uncache jsonapi?
This is due to the internal page cache and Internal dynamic page cache, Drupal will heavily cache all GET requests, so what you are missing is 

$settings['cache']['bins']['page'] = 'cache.backend.null';


as the 3rd bin to clear but this won't work due to dynamic cache, so can you either manually purge the entire Drupal cache or set a timestamp into your URL so you can bypass caching for development.

node/1?_format=json&amp;time=123456789