Sending Emails with Gmail Using MailKit in .NET Web API: The Complete Guide

This guide explains how to send emails using Gmail's SMTP server in a .NET Core Web API application using MailKit, a modern and lightweight email library for .NET. To begin, ensure you have .NET 6 or higher installed, a Gmail account with 2-Step Verification enabled, and an App Password generated. Create a new Web API project and install MailKit via NuGet. Add email configuration settings to the appsettings.json file, including the Gmail email address, App Password, SMTP server, and port. Create an EmailService class that implements the IEmailService interface to handle email sending. The EmailService class uses MailKit to create an email message and send it using Gmail's SMTP server. Register the EmailService in the Program.cs file to make it available for dependency injection. Create an EmailController that uses the EmailService to send emails via a POST endpoint. Test the API by sending a POST request with the recipient's email, subject, and body. If set up correctly, the API should return a success message indicating that the email was sent successfully.