The File Transfer Protocol (FTP) is the Internet service that allows computers to transfer binary files (programs and documents) from one computer to another accross the Internet.. This is the uploading/downloading protocol that you might use to obtain copies of shareware or freeware programs. FTP works in the same way as HTTP for transferring Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet's TCP/IP protocols to enable data transfer. FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).

Usually the user transferring a file needs authority to login and access files on the remote system. The common facility known as anonymous FTP actually works via a special type of public guest account implemented on the remote system.