Sending Emails with Nodemailer and GMail

Prerequisites

• Installed node, npm and git
• Created project folder and npm init and git init done
• Installed node modules with npm install: express, nodemailer, dotenv
• Created Google Cloud Platform account: https://console.cloud.google.com/

Configure secure GMail access

1. 'Open https://console.cloud.google.com/home
2. Press New Project
   
3. Insert project name - Location can be left empty - Click "Create"
   
4. Now the project should be selected like that
   
5. Select "APIs & Services" - "OAuth consent screen"
   
6. Select External and click "Create"
   
7. Enter mandatory fields "App name" / "User support mail" / "Developer contact information" - click "Save And Continue"
   
8. Skip the Scopes page with again clicking "Save and Continue"
9. Add Test User clicking on "+ Add Users"
   
10. Select "Credentials" form the left menue
    
    
11. Create Credentials for OAuth client ID
    
12. Select "Application type" - Web application
    
13. Add https://developers.google.com/oauthplayground at "Authorized redirect URIs" with clicking "+ Add URI" and then click "Create"
    
14. You now should see your Client-ID and Client-Secret - we need them later - press "OK"
    
15. Open OAuth 2.0 Playground: https://developers.google.com/oauthplayground/
16. Select on the left side "Gmail API v1" and there "https://mail.google.com" and click "Authorize APIs"
    
17. Select your GMail-Account you want to use
    
    
18. Allow permissions
    
19. Allow again - to work with emails from GMail
    
    
20. Click on "Exhange authorization code for tokens" to get Refresh Token and Access Token
    
    

Setup the environment-variables and .gitignore

(its important that you NEVER write such secure informations directly in a code which can be unindentionally uploaded to eg. GitHub - allways use instead dotenv and hidden-files like .env which should never get uploaded anywhere stays only locally)

• Create .env file
• Include informations from the GMail configuration (Client-ID and Client-Secret from step 14 and Refresh-Token from stemp 20)

OAUTH_CLIENTID=yourClientID
            OAUTH_CLIENT_SECRET=yourClientSecret
            OAUTH_REFRESH_TOKEN=yourRefreshToken
            MAIL_USERNAME=yourGMailAdress
            MAIL_PASSWORD=yourGMailPassword
            

• Create .gitignore file (if not exists) and add at least to it

.env
            node_modules
            

Do the Coding

• Create new file app.js
• Require necessary modules

const express = require('express')
            const nodemailer = require('nodemailer');
            require("dotenv").config({ path: "./.env" });
            const { gmail } = require('googleapis/build/src/apis/gmail')
            

• Create running express server

const app = express()
            const port = 3000
            app.listen(port, () => {
              console.log(`nodemailerProject is listening at http://localhost:${port}`)
            })
            

• Define the transporter from nodemail (take all the sensitive information for the .env-variables)

let transporter = nodemailer.createTransport({
              service: 'gmail',
              auth: {
                type: 'OAuth2',
                user: process.env.MAIL_USERNAME,
                pass: process.env.MAIL_PASSWORD,
                clientId: process.env.OAUTH_CLIENTID,
                clientSecret: process.env.OAUTH_CLIENT_SECRET,
                refreshToken: process.env.OAUTH_REFRESH_TOKEN
              }
            });
            

• Define mail options

let mailOptions = {
              from: process.env.MAIL_USERNAME,
              to: "[email protected]",
              subject: 'Nodemailer Test Project',
              text: 'Hallo from my nodemailer project'
            };
            

• Send mail with error handling and successfull-message

transporter.sendMail(mailOptions, function(err, data) {
              if (err) {
                console.log("Error " + err);
              } else {
            ### console.log("Email sent successfully");
              }
            });
            

Find the full code here: https://github.com/Rapid1898-code/exampleNodeMailerGMail

If you have any questions or suggestions please get in contact with me: MAIL