Requests follow the JSON API spec and should send the header Accept: application/vnd.api+json. Typical arguments for requests are sent via query params, for more information check the specific requests for each endpoint in the API Reference section. Example: 
curl --request GET \
  --url https://stoplight.io/mocks/zapier/public-api/181772442/zaps \
  --header 'Accept: application/vnd.api+json'