JavaScript Object Notation (JSON) is a lightweight data-interchange format. JSON is self-describing and easy for humans to read and write. It is the most commonly used data format on the web and for RESTful web services.

The following is a simple example of the JSON format describing customer group data containing two customer groups with customer group IDs of 10 and 20, with the additional Description and PaymentTermId fields:

{
  "CustomerGroupId":"10",
  "Description":"Wholesales customers",
  "PaymentTermId":"Net30"
},
{
  "CustomerGroupId":"20",
  "Description":"Retail customers",
  "PaymentTermId":"Receipt"
}

Another little complex example of the JSON data format describing personal details is shown here. The following example represents personal details, including address, phone number, and children and spouse details:

{
  "firstName": "John",
  "lastName": "Smith",
  "isAlive": true,
  "age": 25,
  "address": {
    "streetAddress": "21 2nd Street",
    "city": "New York",
    "state": "NY",
    "postalCode": "10021-3100"
  },
  "phoneNumbers": [
    {
      "type": "home",
      "number": "212 555-1234"
    },
    {
      "type": "office",
      "number": "646 555-4567"
    },
    {
      "type": "mobile",
      "number": "123 456-7890"
    }
  ],
  "children": [],
  "spouse": null
}

As we mentioned earlier, this is easily readable by humans, and at the same time, lighter and easy to parse by a computer program. These characteristics make JSON the preferred data type for web and cloud applications.