app.js

 const express = require("express");
 const bodyParser = require("body-parser");
 const request = require("request");
 const https = require("https");

 const app = express();
 app.use(bodyParser.urlencoded({ extended: true }));

 app.use(express.static("public"));

 app.get("/", function(req, res) {

     res.sendFile(__dirname + "/signup.html");
 });



 app.post("/", function(req, res) {

     const firstName = req.body.firstName;
     const lastName = req.body.lastName;
     const email = req.body.email;

     const data = {
         members: [{
             email_address: email,
             status: "subscribed",
             merge_fields: {
                 FNAME: firstName,
                 LNAME: lastName
             }
         }]
     };

     const jsonData = JSON.stringify(data);

     const url = "https://us8.api.mailchimp.com/3.0/lists/563a0b4066";
     const options = {
         method: "POST",
         auth: "gandalf123:be760d18b19c75d568822c9230e75d7e-us8"
     };

     const request = https.request(url, options, function(response) {


         if (response.statusCode === 200) {
             res.sendFile(__dirname + "/succes.html");
         } else {
             res.sendFile(__dirname + "/failure.html");
         }


         response.on("data", function(data) {
             console.log(JSON.parse(data));
         });

     });

     // console.log(firstName, lastName, email);


     request.write(jsonData);
     request.end();
 });


 app.post("/failure", function(req, res) {
     res.redirect("/");
 });





 app.listen(process.env.PORT || 3000, function() {
     console.log("Server running on port 3000");

 });

 //Api Key:
 //be760d18b19c75d568822c9230e75d7e-us8

 //List id:
 //563a0b4066