Introduction to the JSON APIs and AJAX Challenges

Similar to how User Interfaces help people use programs, Application Programming Interfaces (APIs) help programs interact with other programs. APIs are tools that computers use to communicate with one another, in part to send and receive data. You can use API functionality in your page once you understand how to make requests and process data from it. Programmers often use AJAX technologies when working with APIs.

The term AJAX originated as an acronym for Asynchronous JavaScript And XML. It refers to a group of technologies that make asynchronous requests to a server to transfer data, then load any returned data into the page. An asynchronous process has a couple key properties. The browser does not stop loading a page to wait for the server's response. Also, the browser inserts updated data into part of the page without having to refresh the entire page.

User experience benefits from asynchronous processes in several ways. Pages load faster since the browser isn't waiting for the server to respond in the middle of a page render. Requests and transfers happen in the background, without interrupting what the user is doing. When the browser receives new data, only the necessary area of the page refreshes. These qualities especially enhance the user experience for single page applications.

The data transferred between the browser and server is often in a format called JavaScript Object Notation (JSON). JSON resembles JavaScript object literal syntax, except that it's transferred as a string. Once received, it can be converted into an object and used in a script.

This section covers how to transfer and use data using AJAX technologies with a freeCodeCamp API.

Go to the first lesson