Highcharts offers a small set of APIs designed for plotting charts with dynamic interactions. In order to understand how the APIs work, we must first familiarize ourselves with the chart's internal objects and how they are organized inside a chart. In this chapter, we will learn about the chart class model and how to call the APIs by referencing the objects. Then we build a simple stock price application with PHP, jQuery, and jQuery UI to demonstrate the use of Highcharts APIs. After that, we turn our attention to four different ways of updating a series. We experiment with all the series update methods with the purpose of building an application to illustrate variations in visual effects, and the difference in CPU performance between them. Finally, we investigate performance when updating a series with popular web browsers, in terms of different sizes of datasets. In this chapter, we will cover the following topics: