What is the difference between TCP and UDP?

Transmission Control Protocol, or TCP, is a connection-oriented transport layer protocol that provides reliable, ordered delivery through a three-way handshake, sequence numbers, acknowledgments, and retransmission of lost packets. It is used for applications requiring guaranteed delivery like web browsing, email, and file transfer. User Datagram Protocol, or UDP, is a connectionless protocol that sends packets without establishing a connection or guaranteeing delivery, making it faster but less reliable.