SMTP
SMTP (Simple Mail Transfer Protocol) is a standard internet protocol used for sending and relaying email messages between mail servers. It operates on port 25 (or 587 for secure submission) and defines the rules for communication between email clients and servers, handling message transmission, routing, and delivery. SMTP is a text-based protocol that uses commands and responses to transfer email, but it does not handle email retrieval, which is managed by protocols like POP3 or IMAP.
Developers should learn SMTP when building applications that need to send automated emails, such as notifications, newsletters, or transactional emails (e.g., password resets, order confirmations). It is essential for integrating email functionality into web apps, APIs, or backend systems, and understanding SMTP helps in configuring mail servers, troubleshooting delivery issues, and ensuring compliance with email standards and security practices like SPF and DKIM.