Email remains a crucial communication tool in the digital age, despite the prevalence of smartphones and apps, and is widely used in web applications for notifications and order confirmations. To address challenges like being flagged as SPAM by major email providers, integrating a reputable service like SendGrid, which has established a strong industry presence over the past decade, offers a reliable solution. The text outlines the process of building an API using SendGrid through RapidAPI, detailing the setup of a project with Ruby and Padrino, and the steps to create an endpoint that sends emails with attachments based on user requests. This involves configuring the SendGrid API, encoding attachments in Base64, and testing the functionality to ensure successful email delivery, highlighting the importance of maintaining email reputation and the potential benefits of exploring advanced SendGrid features like Suppression Groups for non-transactional emails.