SMTP Relay Service 101 [Back to Basics] - SendGrid
sendgrid.com › blog › smtp-relay-service-basicsOct 10, 2018 · Simple Mail Transfer Protocol (SMTP) is a straightforward process that allows users to send, relay, and monitor outgoing emails. An SMTP relay service—also commonly known as an SMTP gateway service—takes this a step further by allowing you to send more transaction and marketing-related emails. Instead of managing the logistics of your own program, you can entrust the SMTP relay service to manage and maintain the SMTP server for you.