It’s really simple. Let’s say the URL of the JSON feed you want to grab is example.org/feed.json. Here’s how you’d go about looping through those items in Ruby:

require 'net/http'
require 'json'

response = Net::HTTP.get(URI('https://example.org/feed.json'))
feed = JSON.parse(response)
feed['items'].each do |item|
  # access properties like title by e.g. item['title']
  # see https://jsonfeed.org/version/1 for full spec
end

Here’s a full working example of what this looks like. It’s incredibly simpler and much more fun to work with than XML. Not even close.