Rails5.x config/initializers/mime_types.rb

Mime::Type.register "gzip/json", :gzipjson

ActionDispatch::Http::Parameters::DEFAULT_PARSERS[:gzipjson] = lambda do |raw_body|
  body = ActiveSupport::Gzip.decompress(raw_body)
  JSON.parse(body)
end

ActionDispatch::Request.parameter_parsers = ActionDispatch::Request::DEFAULT_PARSERS

http client

• add content type header Content-Type:gzip/json
• add Content encoding header Content-Encoding:gzip
• gzip inflate to request body
• request !!