What is the difference between TCP and UDP?

Network interaction on the internet is based on a variety of data transport protocols, among which the most popular are TCP and UDP, which perform fundamentally different tasks. To choose the right tool for your application, it is important to understand the key differences between them and their use cases. The TCP protocol is designed to ensure maximum reliability of information delivery, whereas UDP focuses on speed and minimal latency for real-time data transmission.

The technical features of these protocols determine their behavior under various load scenarios. The TCP protocol guarantees that all sent packets will reach the receiver in the correct sequence, because before transmission begins, it establishes a connection through a three-way handshake procedure, and during operation, it constantly requests acknowledgments of data receipt. UDP works completely differently: the device simply sends packets to the receiver without prior connection checks and without waiting for acknowledgments, which makes it extremely fast but completely unreliable in unstable network conditions.

The use cases of TCP and UDP differ drastically due to their architectural properties:

The choice between these protocols always boils down to a balance between reliability and speed. If you are developing a financial system, you need only TCP with its delivery guarantees. If you are creating a multiplayer shooter where a character's position is updated dozens of times per second, the loss of a single packet with coordinates does not matter, so developers choose the fast UDP protocol.