How do you implement batch email sending with SendGrid API in Spring Boot?

Table of Contents

• Introduction
• Setting Up Batch Email Sending with SendGrid API in Spring Boot
  • 1. Add Dependencies
    • a. Add SendGrid Dependency
    • b. Add Spring Boot Dependencies
  • 2. Configure SendGrid API Key
    • a. Store the API Key in application.properties
    • b. Configure SendGrid Client
  • 3. Implement Batch Email Sending
    • a. Define the Email Sending Service
    • b. Calling the Email Service
  • 4. Testing Batch Email Sending
• Conclusion

Introduction

Sending bulk emails efficiently is a common requirement for applications that need to notify many recipients at once. SendGrid, a cloud-based email delivery service, offers an easy-to-use API for sending emails, including batch or bulk email functionality. In this guide, we will demonstrate how to implement batch email sending using SendGrid API in a Spring Boot application.

Setting Up Batch Email Sending with SendGrid API in Spring Boot

1. Add Dependencies

To interact with SendGrid's API in your Spring Boot application, you need to include the required dependencies.

a. Add SendGrid Dependency

In your pom.xml file, add the following dependency for SendGrid:

This allows your application to use SendGrid’s Java SDK for email sending.

b. Add Spring Boot Dependencies

If you haven't already, make sure you have the Spring Boot starter for web services to handle HTTP requests:

2. Configure SendGrid API Key

Before sending emails, you need to configure your SendGrid API key. It is important to securely store your API key and not hard-code it in your application.

a. Store the API Key in application.properties

b. Configure SendGrid Client

In your Spring Boot application, you can create a configuration class to set up SendGrid's client using the API key from the application properties.

SendGridConfig.java:

3. Implement Batch Email Sending

Now that the SendGrid client is set up, you can proceed with sending emails in batches. SendGrid allows sending emails to multiple recipients by including them in the Personalization object.

a. Define the Email Sending Service

You can create a service to handle sending emails. This service will loop through the list of recipients and send the emails.

EmailService.java:

In this example, the sendBatchEmail method adds multiple recipients by looping through the recipients list and attaching each one to the Mail object’s Personalization section.

b. Calling the Email Service

Now, you can create a controller to trigger the batch email sending process.

EmailController.java:

In this controller, we define an endpoint POST /email/send-batch that accepts a list of recipient email addresses. This endpoint calls the sendBatchEmail method of the EmailService to send the emails.

4. Testing Batch Email Sending

To test the batch email functionality:

1. Start your Spring Boot application.
2. Use Postman or any API testing tool to send a POST request to http://localhost:8080/email/send-batch with a JSON array of email addresses as the body:

3. Upon successful execution, the recipients will receive the same email, and you'll get a confirmation message.

Conclusion

Implementing batch email sending with SendGrid in Spring Boot is a straightforward process that involves setting up SendGrid's API, configuring the client, and using personalization to send bulk emails. The key steps include adding dependencies, configuring the SendGrid API key, and looping through a list of recipients to send them emails. By using this approach, you can efficiently send emails to multiple recipients in your application.