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JSON is a lightweight data format used for exchanging and storing data. It is easy for humans to read and write and easy for machines to parse and generate. JSON is widely used in APIs, web applications, and data storage.
Lightweight & Fast
Human-Readable & Easy to Write
Language-Independent
Uses Key-Value Pairs
key: value format.Commonly Used in APIs
<span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"name"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"John Doe"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"age"</span><span class="pun">:</span><span class="pln"> </span><span class="lit">30</span><span class="pun">,</span><span class="pln"> </span><span class="str">"email"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"john@example.com"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"isStudent"</span><span class="pun">:</span><span class="pln"> </span><span class="kwd">false</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span>
<span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"employees"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">[</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"id"</span><span class="pun">:</span><span class="pln"> </span><span class="lit">1</span><span class="pun">,</span><span class="pln"> </span><span class="str">"name"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"Alice"</span><span class="pln"> </span><span class="pun">},</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"id"</span><span class="pun">:</span><span class="pln"> </span><span class="lit">2</span><span class="pun">,</span><span class="pln"> </span><span class="str">"name"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"Bob"</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">]</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span>
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:
<span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"CustomerGroupId"</span><span class="pun">:</span><span class="str">"10"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"Description"</span><span class="pun">:</span><span class="str">"Wholesales customers"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"PaymentTermId"</span><span class="pun">:</span><span class="str">"Net30"</span><span class="pln"> </span><span class="pun">},</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"CustomerGroupId"</span><span class="pun">:</span><span class="str">"20"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"Description"</span><span class="pun">:</span><span class="str">"Retail customers"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"PaymentTermId"</span><span class="pun">:</span><span class="str">"Receipt"</span><span class="pln"> </span><span class="pun">}</span>
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:
<span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"firstName"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"John"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"lastName"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"Smith"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"isAlive"</span><span class="pun">:</span><span class="pln"> </span><span class="kwd">true</span><span class="pun">,</span><span class="pln"> </span><span class="str">"age"</span><span class="pun">:</span><span class="pln"> </span><span class="lit">25</span><span class="pun">,</span><span class="pln"> </span><span class="str">"address"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"streetAddress"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"21 2nd Street"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"city"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"New York"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"state"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"NY"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"postalCode"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"10021-3100"</span><span class="pln"> </span><span class="pun">},</span><span class="pln"> </span><span class="str">"phoneNumbers"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">[</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"type"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"home"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"number"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"212 555-1234"</span><span class="pln"> </span><span class="pun">},</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"type"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"office"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"number"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"646 555-4567"</span><span class="pln"> </span><span class="pun">},</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="str">"type"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"mobile"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"number"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"123 456-7890"</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">],</span><span class="pln"> </span><span class="str">"children"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">[],</span><span class="pln"> </span><span class="str">"spouse"</span><span class="pun">:</span><span class="pln"> </span><span class="kwd">null</span><span class="pln"> </span><span class="pun">}</span>
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.
| Feature | JSON | XML |
|---|---|---|
| Readability | Easy to read | More complex |
| Size | Smaller | Larger |
| Parsing Speed | Fast | Slow |
| Supported in APIs | Mostly used in REST APIs | Used in SOAP APIs |
| Data Structure | Key-Value pairs | Tags and attributes |
✅ APIs (REST, OData, GraphQL)
✅ Web & Mobile Applications
✅ Database Storage (NoSQL databases like MongoDB)
✅ Configuration Files (.json for settings in applications)