Customizing Firebase Email Templates: A Step-by-Step Guide
When using Firebase Authentication, you may want to customize the email templates sent to users for actions like password reset and email verification. However, Firebase offers limited customizability due to security measures. In this tutorial, we’ll explore a solution to overcome this limitation and use customized email templates with Firebase.
Prerequisites
Before we begin, make sure you’re familiar with JavaScript, Firebase, and Express. You’ll also need Node.js installed on your machine. We’ll be using React for the frontend, but you can follow along with other frameworks or vanilla JavaScript.
The Problem with Firebase Email Templates
Normally, you’d go to the Templates section on the Authentication page of your Firebase project to customize email templates. However, Firebase only allows limited customization, such as changing the sender name, reply-to field, and action URL. This often isn’t sufficient for the level of detail you want in your emails.
Solving the Problem
To send customized email templates, we’ll create a backend to send emails ourselves using the Firebase Admin SDK. We’ll generate an email action link that will be embedded in emails sent to users. When a user clicks the link, it will be processed by Firebase to carry out the intended action, such as verifying a user’s email or resetting their password.
Setting Up the React and Express App
We’ll use starter repos for both the React and Express apps to focus on the topic at hand. Clone the repos and set up the necessary Firebase configuration.
Creating an Express API to Send Customized Email Templates
To create the route that sends customized verification emails, we’ll complete four steps:
- Initialize the Firebase Admin SDK: Add a Firebase project, enable authentication, and generate a private key for initialization.
- Generate an email action link: Use the Firebase Admin SDK to generate a link that will be embedded in emails sent to users.
- Embed the link in the email template: Use EJS, a template engine, to embed the link in the email template.
- Send emails using SendGrid: Set up SendGrid to send transactional emails.
Initializing the Firebase Admin SDK
To initialize the Firebase Admin SDK, add a Firebase project, enable authentication, and generate a private key. Then, move the private key file to the root directory of your Express app and rename it serviceAccountKey.js. Remove all properties except for project_id, private_key, and client_email, and copy the property values to the corresponding variables in the .env file.
Generating the Email Verification Action Link
Use the Firebase Admin SDK to generate an email verification action link. Add a POST route that receives the necessary data from the request body and uses it to send an email to the user.
Working on the Email Template
Create an email template using EJS and modify the anchor tag to use the generated action link. Then, set up SendGrid to send transactional emails.
Setting Up SendGrid
Register for a free SendGrid account, create a sender identity, and generate an API key. Then, add the API key to your .env file and use it to send emails.
Using the API in the Frontend React Application
In the React app, create a sendEmail.js file and add a function that sends a POST request to the API with the user’s email and redirect URL attached to the body. Then, replace the sendEmailVerification function in the Register.js and Login.js files with the new function.
Conclusion
In this tutorial, we learned how to send customized emails using Firebase Authentication. By following these steps, you can customize emails sent to your users to match the visuals of your application.