Web graphing libraries
These are some good, free, open-source libraries for drawing graphs/charts in web pages.
ApexCharts
I reckon this is the best. It uses SVG, so the graphs can be responsive to changes in screen width. There are a good variety of chart types for an SVG-based library. It’s a simple library to include in your site. Documentation is good.
Frappe Charts
A compact, simple, library – inspired by GitHub. This also uses SVG. Fewer chart types than ApexCharts. It currently doesn’t let you control the minimum/maximum y-axis values. Still very good if the chart types it offers appeal to you.
Chartist.js
A very compact SVG-based library. Requires plug-ins for things such as time-based charts.
gionkunz.github.io/chartist-js/
Apache ECharts
Powerful, but large and uses the canvas rather than SVG. It has many more chart types than the SVG-based libraries but is not as responsive to screen size changes.