What does the json_encode() function do in PHP?

The json_encode() function in PHP is designed to convert PHP variables, such as arrays and objects, into a JSON-formatted string. This function is essential for APIs and data interchange between different programming languages, as JSON (JavaScript Object Notation) is a widely used format for data exchange.

When invoking json_encode(), it takes a PHP variable as input and serializes it into a valid JSON string that can be easily transmitted or stored. This is particularly useful when you need to prepare data for use in JavaScript or when sending data over the web in a RESTful API.

For example, if you have an associative array in PHP, using json_encode() will create a JSON string representation of that array, which can then be sent to a client-side application or saved to a file for later use.

This functionality is crucial for modern web applications that rely on a seamless interaction between the client and server in a format that is easy to parse and process by various programming languages.