How to Send Emails Using Firebase Cloud Functions

Send Emails Using Firebase Cloud Functions

Firebase is a powerful platform for building mobile and web applications. It offers many features, such as authentication, a real-time database, and cloud storage. However, one of the most valuable features of Firebase is Cloud Functions. Cloud Functions are event-driven, serverless functions triggered by Firebase events. One everyday use case for Cloud Functions is sending emails. In this blog post, we will explore how to use Cloud Functions to send emails in response to events in Firebase.

What are Cloud Functions?

Cloud Functions is a serverless computing platform that allows you to run code in response to events without managing a server. Cloud Functions can be written in JavaScript, Python, or Go and are executed in a controlled environment.

You can use Cloud Functions to respond to events generated by Firebase products, such as changes to data in the Realtime Database, new user signups via Auth, and incoming HTTP requests from Cloud Hosting. Your custom events can also trigger Cloud Functions.

Using Cloud Functions for Firebase allows you to extend the functionality of your app without having to write any backend code or manage any infrastructure. Instead, you must register and deploy your functions, and Firebase will take care of the rest.

What is Firebase?

Firebase is a cloud-based platform that helps you develop apps quickly and efficiently. It provides you with all the tools you need to create high-quality apps, including a real-time database, user authentication, static hosting, and more. Firebase also makes it easy to scale your app by adding new features as you need them.

Sending Emails with Cloud Functions

Cloud Functions for Firebase provides a set of pre-configured event triggers that allow you to automatically run a function in response to specific events in your project. One such motivation is the “send email” trigger, which can be used to send an email when certain events occur in your project.

To use the “send email” trigger, specify the recipient’s email address and the message you wish to send. The “send email” trigger will then send the email to you.

There are a few things to keep in mind when using the “send email” trigger:

– The “send email” trigger is asynchronous, so your function will continue running even after the email has been sent.

– The “sendEmail” trigger only supports sending plain text emails. If you need to send HTML emails, you’ll need to use another service, such as SendGrid.

– The “send email” trigger is unsuitable for sending large amounts of emails (e.g., bulk mailing). Again, you’ll need to use another service, such as Mailgun.

Setting up the Cloud Function

Assuming you have a Firebase project set up and are using the Firebase CLI, setting up a Cloud Function is easy. Just run the following command from your project’s root directory:

Firebase init functions

This will set up some boilerplate code for your function and create a new file, functions/index.js. You can now write your function in this file. For our purposes, we’ll use a simple function that sends an email when it’s triggered:

exports.send email = functions.database.ref(‘/messages/{messageId}’).onWrite(event => {

const message data =;

if (message data) {

const msg = {

to: ‘[email protected]’,

from: ‘[email protected]’,

subject: ‘New Message,’

text: messageData.text,

html: `




return mailTransport.sendMail(msg);


return null;


Testing the Cloud Function

To test the function, you will need to do the following:

1. Log into your Firebase account and go to the console.

2. Click on the project you want to use for this tutorial.

3. Click on the “Functions” tab from the project overview page.

4. Click on the “test” button for your function. This will open up a new window where you can enter some test data.

5. In the “Function request body” field, enter the following JSON: { “to”: “[email protected],” “subject”: “Hello from Cloud Functions,” “body”: “This is a test!” }

6. Click on the “Test” button to run your function with the given data.

7. If everything worked correctly, you should receive an email at the address specified in the JSON data!


Cloud Functions for Firebase are a great way to send email from your app. You can use them to send welcome emails, confirmation emails, or any other email you need. The best part is that they’re free and easy to set up. So if you’re looking for an easy way to send email from your app, Cloud Functions for Firebase is a great option.

Also Read: How to Encrypt Email in Outlook

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Anthony Goldstein is an American author from California. He is best known for his work in the tech industry, where he has written extensively on topics such as artificial intelligence and the future of technology.

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