Email Glossary

SMTP Server

An SMTP server is a mail server that implements the Simple Mail Transfer Protocol. When you send email, your mail client connects to an SMTP server via ports 25, 587, or 465. The SMTP server relays the message to the recipient's mail server for final delivery.

SMTP Server Ports

Port 25 is the standard SMTP port but is often blocked by ISPs and cloud providers. Port 587 (STARTTLS) is the recommended submission port for authenticated sending. Port 465 (SMTPS) uses SSL/TLS encryption immediately on connection.

Related Terms

SMTP Relay

A third-party SMTP server that routes your outgoing emails through trusted IP infrastructure.

Email API

A programmatic interface for sending, receiving, and managing emails from your application code.

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