Postgres is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. It is used to store data securely, support best practices, and allow recovering them when the request is processed. PostgreSQL is cross-platform and runs on various operating systems such as Microsoft Windows, UNIX, FreeBSD, Mac OS X, Solaris, HP-UX, LINUX, and so on. It is also the existing database for the macOS server.