json This module implements the json data type for storing JSON data in PostgreSQL. The advantage of using the json type over storing JSON data in a text field is that it performs JSON validation automatically, and there will be several type-safe functions for manipulating JSON content. The json type stores valid JSON "values" as defined by json.org. That is, a json field can hold a string, number, object, array, 'true', 'false', or 'null'. Be warned, though, that the JSON standard defines a top-level JSON text as an object or array, and many JSON libraries will only accept an object or array. The json datatype is stored internally as JSON-formatted text and condensed, on input, to the smallest size possible If the server encoding is not UTF-8, escapes representing non-ASCII characters (e.g. "\u266B") are not converted to their respective characters (even when the server encoding has them) because it would introduce a performance penalty. . For example, SELECT ' "json\u0020string" '::json; will yield '"json string"'. Also, bear in mind that JSON null ('null'::json) and SQL NULL (NULL::json) are two different things. The json module is currently under development. Function Return Type Description Example Result json_validate(text) boolean Determine if text is valid JSON. json_validate('{key: "value"}') false json_validate('{"key": "value"}') true json_get_type(json) json_type -  one of: 'null' 'string' 'number' 'bool' 'object' 'array' Get the type of a json value. json_get_type('{"pi": "3.14159", "e": "2.71828"}') 'object' json_stringify(json) text Convert json to text. Currently, json_stringify(x) is equivalent to x::text. json_stringify('{"key":"value","array":[1,2,3]}') {"key":"value","array":[1,2,3]} json_stringify(json, indent text) text Convert json to text, adding spaces and indentation for readability. json_stringify('{"a":true,"b":false,"array":[1,2,3]}', ' ') { "a": true, "b": false, "array": [ 1, 2, 3 ] } Joey Adams joeyadams3.14159@gmail.com Development of this module was sponsored by Google through its Google Summer of Code program (code.google.com/soc).