macOS Server, formerly Mac OS X Server and OS X Server, is a series of Unix-like server operating systems developed by Apple Inc. and based on macOS (formerly Mac OS X and OS X). macOS Server adds server functionality and system administration tools to macOS and provides tools to manage both macOS-based computers and iOS-based devices. macOS Server provides network services such as a mail transfer agent, AFP and SMB servers, an LDAP server, and a domain name server, as well as server applications including a Web server, database, and calendar server.