JSON structure-------------------------What are '{} and '[]' are in API json request format

• JSON:
• JSON: JavaScript Object Notation.
• JSON is a syntax for storing and exchanging data.
• JSON is an easier-to-use alternative to XML.

• JSON syntax: 
• It is derived from JavaScript object notation syntax:
• Data is in name/value pairs
• Data is separated by commas
• Curly braces hold objects
• Square brackets hold arrays (multiple objects)
• [] -- looks like it is for bunch(multiple sets) of related items
• {} -- looks like it is for one set of related item.
• "" -- looks like every name and value should be in double quotes
• Note: Looks like each set has "name" and "value" with colon seperated. Comma seperated.
• JSON uses JavaScript syntax, but the JSON format is text only, just like XML.
• Text can be read and used as a data format by any programming language.
• JSON names require double quotes. JavaScript names don't.

• JSON Example:

{"employees":[
    {"firstName":"John", "lastName":"Doe"},
    {"firstName":"Anna", "lastName":"Smith"},
    {"firstName":"Peter", "lastName":"Jones"}
]}

• XML Example:

<employees>
    <employee>
        <firstName>John</firstName> <lastName>Doe</lastName>
    </employee>
    <employee>
        <firstName>Anna</firstName> <lastName>Smith</lastName>
    </employee>
    <employee>
        <firstName>Peter</firstName> <lastName>Jones</lastName>
    </employee>
</employees>

• JSON Files
• The file type for JSON files is ".json"
• The MIME type for JSON text is "application/json"