12th September 2019: PostgreSQL 12 Beta 4 Released!
Supported Versions: Current (11) / 10 / 9.6 / 9.5 / 9.4
Development Versions: 12 / devel
Unsupported versions: 9.3 / 9.2 / 9.1 / 9.0 / 8.4 / 8.3 / 8.2 / 8.1 / 8.0
This documentation is for an unsupported version of PostgreSQL.
You may want to view the same page for the current version, or one of the supported versions listed above instead.

G.4. Extensions

PostgreSQL is designed to be easily extensible. For this reason, extensions loaded into the database can function just like features that are built in. The contrib/ directory shipped with the source code contains several extensions, which are described in Appendix F. Other extensions are developed independently, like PostGIS. Even PostgreSQL replication solutions can be developed externally. For example, Slony-I is a popular master/standby replication solution that is developed independently from the core project.