PostgreSQL is more than a relational database and an SQL language. PostgreSQL is now home to different NoSQL data types. The power of PostgreSQL and schemaless data stores enable the developers to build reliable and flexible applications in an agile way.

PostgreSQL supports the JavaScript Simple Object Notation (JSON) data type, which is often used to share data across different systems in modern RESTful web applications. In PostgreSQL release 9.4, PostgreSQL introduced another structured binary format to save JSON documents instead of using the JSON format in the prior versions. The new data type is called JSONB. This data type eliminates the need to parse a JSON document before it is committed to the database. In other words, PostgreSQL can ingest a JSON document at a speed comparable with document databases, while still maintaining compliance with ACID. In PostgreSQL version 9.5 several functions are added to make handling JSON documents much easier. In version 10, full text search is supported for JSON and JSONB documents.

Key/value pairs are also supported by the PostgreSQL hstore extension. The Hstore is used to store semi-structured data, and it can be used in several scenarios to decrease the number of attributes that are rarely used and often contain null values.

Finally, PostgreSQL supports the Extensible Markup Language (XML) data type. XML is very flexible and it is often used to define document formats. XML is used in RSS, Atom, SOAP, and XHTML. PostgreSQL supports several XML functions to generate and create XML documents. Also, it supports xpath to find information in an XML document.