JSON is a recursive data format; at the top level a JSON object is a dictionary that holds key/value pairs, and it can hold more dictionaries within it, which themselves will hold key/value pairs.

JSON files can hold these data types:

Note that it has no comments and no date type. All data must fall into one of these categories. On parse, however, it is common to parse specified values into a proper type[1], like an ISO 8601 date could be regexed into the proper Date format, etc.

Trailing commas are not allowed, and all strings must be quoted with double quotes, not single quotes.


  "string": "hello, world!",
  "number": 1,
  "boolean": true,
  "array": [1,2,3],
  "dictionary": {
    "nested key": "nested value"
  "null": null


Because JSON is a recursive data format without complex types, it is easy to parse from a programming standpoint. A pseudocode example:

CREATE output AS an empty hash map or dictionary

FUNCTION parse_dict HAS PARAMETERS raw_dict, parsed_dict
  FOR key, value IN dict
    IF key IS NOT A hash map or dictionary
      # Here you could place a conditional to to parse special types, like dates
      SET parsed_dict[key] TO value
      SET parsed_dict[key] TO empty hash map or dictionary
      CALL parse_dict WITH key, value, parsed_dict[key]
    END IF

OPEN json file
SET json_contents TO contents of json file

CALL parse_dict WITH json_contents, output

RETURN output


  1. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
  2. https://en.wikipedia.org/wiki/JSON
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Last modified: 202206230948