Sending bulk emails in Node.js using SendGrid API

What is SendGrid API? 
SendGrid is a platform for sending transactional and marketing emails to the customers. It provides scalability, reliability, and deliverability which is an important issue for an organization.
Benefits of using SendGrid API:

• If you are using Nodemailer with Gmail then you can send only certain amount of emails per day.
• Also, there is no need to set up your own SMTP server.
• SMTP doesn't provide the deliverability, i.e. email may or may not be sent.

Steps to send emails using SendGrid API:

1. Setting up an API key: 
   
   • Go to sendgrid dashboard and click on create api key button.
      
   • Name the API-key as you want, for this tutorial we'll name it node-mail
   Copy the API-key as for security reasons you may not be able to see it again.
2. Setting up a node.js app:
   
   • Create an empty NPM package using the command. (The -y flag which is passed is used to use the defaults in the generator instead of asking questions)
      

     npm init -y

   • Create a file named index.js and add a boiler plate code. index.js

     // Importing http library
     const http = require("http");
     
     const PORT = 3000; // Defining PORT
     
     http.createServer((req, res) => {
     
         // Output Hello World on HTML page
         res.write("<h1>Hello World!</h1>");
         res.end();
     })
     
     // Initializing server
     .listen(PORT,() => console.log(`Server running on PORT : ${PORT}`));
     

   • Now run the code by using node index command and go to 127.0.0.1:3000 link. You will see the output.
   • 
     And in console 
      
3. Installing SendGrid library: Install the SendGrid library by running the below command

   npm i @sendgrid/mail

4. Sending emails by using library: javascript

   const http = require("http");
   
   const PORT = 3000;
   
   http.createServer((req, res) => {
   
       // Initializing sendgrid object
       const mailer = require("@sendgrid/mail");
   
       // Insert your API key here
       mailer.setApiKey("<your-api-key>");
       
       // Setting configurations
       const msg = {
         to: ["[email protected]", "[email protected]"],
         from: "[email protected]",
         subject: "Message sent for demo purpose",
         html:
           "<h1>New message from Geeksforgeeks</h1> 
            
   <p>Some demo text from geeksforgeeks.</p>
   "
       };
   
       // Sending mail
       mailer.send(msg, function(err, json) {
         if (err) {
           console.log(err);
   
           // Writing error message
           res.write("Can't send message sent");
         } else {
   
           // Writing success message
           res.write("Message sent");
         }
       });
   
       res.end();
     })
   .listen(PORT, () => console.log(`Server running on PORT : ${PORT}`));