Hey @asoola ,
For your first question: the shopify-api-node library works with the Admin API only by default (/admin/api is the pathname specified in the library etc).
For your second question: you can use the shopify.callGraphqlLimits property to see the limits for a GraphQL Admin API call, e.g. with
shopify.on('callGraphqlLimits', (limits) => console.log(limits));
the value of which will be an object like:
{ restoreRate: 50, remaining: 998, current: 2, max: 1000 }