Senior SMTP and MTA Engineer · Engineering
Works on SMTP delivery, queues and retry logic. Explains bounce codes, deferrals and connection behaviour from the sending server side.
Mateus works on the SMTP delivery layer: connection handling, queues, retry schedules and how replies from receiving servers are classified. He writes about what actually happens between a send request and the recipient mail server.
His articles decode SMTP reply codes and enhanced status codes, explain the difference between a deferral and a hard bounce, and show how to read delivery logs to find the real cause of a failure.
He is the technical reviewer for most SMTP protocol content on the help center.
SMTP reply codes, bounce handling, throttling, queues and retries, TLS
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