PostgreSQL offers many features designed to assist developers in creating applications, enable administrators to safeguard data integrity, develop fault-tolerant environments, and help you manage any data size efficiently. Being free and open-source, PostgreSQL stands out for its high extensibility. You can define custom data types, create unique functions, and integrate code from various programming languages without recompiling your database.
PostgreSQL strives for compliance with the SQL standard, except where adhering to it would compromise its traditional features or lead to suboptimal design choices. It supports many SQL standard features, albeit sometimes with minor variations in syntax or functionality. Over time, ongoing efforts have been made to enhance its compliance with the SQL standard.