What it JSON?
JavaScript Object Notation (JSON) is a lightweight text-based, language-independent data exchange format. JSON defines a small set of formatting rules for the portable representation of structured data. JSON can represent four primitive types (strings, numbers, boolean values, and null) and two structured types (objects and arrays). JSON is used to exchange data between applications written in many programming languages, including JavaScript, Java, C++, C#, Go, PHP, Python, and many others.
How to request data in JSON format?
To get data in JSON format from the server, the client must explicitly tell the server that it expects JSON by sending the Accept: application/json request header. Without the Accept header, the server may automatically send data in a different format that it thinks is best for the API client (based on the UserAgent header), and it might not be JSON.
How to send and receive JSON data using JavaScript?
JSON data is transmitted over the network as a text string and must be converted to a JavaScript object before using it. Likewise, before sending JavaScript objects over the network in JSON format, they must be converted to strings. JavaScript has two built-in functions for converting JavaScript objects to JSON and vice versa:
- JSON.parse() - converts a JSON string to a JavaScript object.
- JSON.stringify() - converts a JavaScript object to a JSON string.
JSON Request Example
An example of an HTTP GET request to fetch JSON data from a ReqBin echo URL.
The server response to our client's request.
The server returned JSON in the body of the HTTP response message. The Content-Length: 19 header indicates the length of the JSON data in the response body, and the Content-Type: application/json response header indicates the type of data.
JSON MIME Type
The official MIME type for JSON is application/json: