example.js

var apiKey = 'cueqNZUb3ldeWTNX7MU3Mel8UXtaAMUi';
var easypost = require('./lib/main.js')(apiKey); // after installing with NPM this can be require('node-easypost')(apiKey);

// set addresses
var toAddress = {
	name: "Sawyer Bateman",
	street1: "1A Larkspur Cres.",
	city: "St. Albert",
	state: "AB",
	zip: "t8n2m4",
	country: "CA",
	phone: "780-123-4567"
};

var fromAddress = {
	name: "EasyPost",
    street1: "164 Townsend St",
	street2: "#1",
	city: "San Francisco",
	state: "CA",
	zip: "94107",
	phone: "415-123-4567"
};

// verify address
easypost.Address.create(fromAddress, function(err, fromAddress) {
	fromAddress.verify(function(err, response) {
		if (err) {
			console.log('Address is invalid.');
		} else if (response.message !== undefined && response.message !== null) {
			console.log('Address is valid but has an issue: ', response.message);
			var verifiedAddress = response.address;
		} else {
			var verifiedAddress = response;
		}
	});
});

// set parcel
easypost.Parcel.create({
	predefined_package: "InvalidPackageName",
	weight: 21.2
}, function(err, response) {
	console.log(err);
});

var parcel = {
	length: 10.2,  // inches
	width: 7.8,    // inches
	height: 4.3,   // inches
	weight: 21.2   // ounces
};

// create customs_info form for intl shipping
var customsItem = {
  description: "EasyPost t-shirts",
  hs_tariff_number: 123456,
  origin_country: "US",
  quantity: 2,
  value: 96.27,
  weight: 21.1
};

var customsInfo = {
  customs_certify: 1,
  customs_signer: "Hector Hammerfall",
  contents_type: "gift",
  contents_explanation: "",
  eel_pfc: "NOEEI 30.37(a)",
  non_delivery_option: "return",
  restriction_type: "none",
  restriction_comments: "",
  customs_items: [customsItem]
};

// create shipment
easypost.Shipment.create({
  to_address: toAddress,
  from_address: fromAddress,
  parcel: parcel,
  customs_info: customsInfo
}, function(err, shipment) {
    // shipment.lowestRate filters by carrier name and service name, and accepts negative filters by preceding the name with an exclamation mark
    shipment.buy({rate: shipment.lowestRate(['USPS', 'ups'], '!LibraryMail, !mediaMAIL'), insurance: 100.00}, function(err, shipment) {
		console.log(shipment);
    });
});