I am sending an E-mail to the User in Flutter using Firebase Cloud Functions.

1. Install NodeJS: -

Download NodeJS Click here

Install Node.js skip the additional features.

After installing successfully verify that NodeJS is installed successfully or not using the following CMD command

node -v

You get the installed version number of NodeJS.

2. Install Firebase Tools: -

Write the following command to install Firebase Tools CMD

npm install -g firebase-tools

3. Login to Firebase: -

firebase login

It will open a web browser and you must log in with your Google Account.

4. Create Project: -

Open the Firebase Console

Create a new project.

Setup with the default settings no need to change anything.

Open the File Explorer.

Create a new folder where you want to create a project.

mkdir sendMail
cd sendMail

Initialize the Firebase project on local pc

firebase init

Enter y

Select Language: JavaScript

Go with the default settings.

And your Firebase Project is created on a Local PC.

Open the VS-Code and open that folder.

5. Install packages: -

To send mail you have to install 2 packages.

After opening your project in VS-Code.

cd functions 
npm install nodemailer
npm install cors

6. Setup your G-mail Account: -

Please don’t use your account.

Open the Google page and sign in with your account.

Open the following two links and enable both.

1. Less Secure app access
2. Display unblock captcha

7. Write a function to send mail: -

Under the functions folder, index.js write code to send mail as below.

You can use your own HTML as a body.

You can also take the username as an argument to display its name in the mail

const functions = require('firebase-functions');
const admin = require('firebase-admin');
const nodemailer = require('nodemailer');
const cors = require('cors')({origin: true});
admin.initializeApp();
let transporter = nodemailer.createTransport({
service: 'gmail',
auth: {
user: 'agile.developers1804@gmail.com',
pass: '*******'  //you your password
}
});
exports.sendMail = functions.https.onRequest((req, res) => {
cors(req, res, () => {
// getting dest email by query string
const dest = req.query.dest;
const mailOptions = {
from: 'Agile Developers <agile.developers1804@gmail.com>', // 
to: dest,
subject: 'Welcome to ABC', // email subject
html: `Dear User, Welcome to ABC, <p>thank you for choosing us      `
};
// returning result
return transporter.sendMail(mailOptions, (erro, info) => {
if(erro){
return res.send(erro.toString());
}
return res.send('Sended');
});
});
});

8. Run the Function: -

//TO-DO go-to your project folder
firebase serve
//here you can find your URL to test Firebase Cloud Function

Here you can find the URL to call that function. You can call that function using the following URL

http://localhost:5000/fcfdemo-b3a7f/us-central1/sendMail?=”destEmailID”

Example: — http://localhost:5000/fcfdemo-b3a7f/us-central1/sendMail?=bhavikvashi180498@gmail.com

9. Deploy the Firebase Function: -

Go to your project directory

Open cmd here

firebase deploy

10. Open Firebase Console and Grab the Deployed URL: -

Open Firebase Console

Here you can find the URL of deployed Firebase function.

In this case, your URL is: https://us-central1-fcfdemo-b3a7f.cloudfunctions.net/sendMail

11. Create a Flutter project and use this URL to send mail: -

You can also accept mail via TextFormField to make it more accurate.

Use I have just used my Email ID to send

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: HomePage(),
);
}
}
class HomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Firebase Cloud Function"),),
body: Center(
child: RaisedButton(
onPressed: ()async{
var res=await http.get('https://us-central1-fcfdemo-   b3a7f.cloudfunctions.net/sendMail?dest=bhavikvashi180498@gmail.com');
print(res.body);
},
child: Text('Send Mail'),
),
),
);
}
}

12. Run Firebase Cloud Function: -

Run your app

Press the Button Send Mail

And receiver has new mail in his Inbox