// Install and Require postmark library => npm install postmark:
var postmark = require("postmark");

// Send an email:
var client = new postmark.Client("POSTMARK-SERVER-API-TOKEN-HERE");

client.sendEmail({
  "From": "sender@example.com",
  "To": "recipient@example.com",
  "Subject": "Test",
  "TextBody": "Hello from Postmark!"
});