PostgreSQL is the world’s most advanced open source database and the fourth most popular database. In development for more than 20 years, PostgreSQL is managed by a well-organized and highly principled and experienced open source community. It is an object-oriented database that is fully ACID compliant and highly extensible, enabling the community to add new features and capabilities as workload demands evolved.
Because of its extensibility, PostgreSQL offers a wide variety of built-in data types including JSON, XML, HSTORE (key-value), Geo-spatial (PostGIS), IPv6; flexible indexing, featuring composite indexes, GiST, SP- GiST, GIN; full Text Search, online index reorganization; background workers such as a managed process known as Mongress, which accepts MongoDB queries to interface with Postgres data; a contrib module interface: pgcrypto (data encryption), pg_trgm (find 'similar' data), HSTORE (schema-less data); and extensive SQL support.
PostgreSQL runs on all major operating systems, including Linux, UNIX (AIX, BSD, HP-UX, macOS, Solaris), and Windows. It offers the following programming languages: PL/pgSQL, PL/SQL, Java, Python, Ruby, C/C++, PHP, Lisp, Scheme, and Qt.