Circos is described as 'software package for visualizing data and information. It visualizes data in a circular layout — this makes Circos ideal for exploring relationships between objects or positions'. There are more than 25 alternatives to Circos for a variety of platforms, including Online / Web-based, Self-Hosted solutions, Mac, Windows and Linux. The best alternative is D3.js, which is both free and Open Source. Other great apps like Circos are Tableau (Paid), RAWGraphs (Free, Open Source), Plotly (Freemium, Open Source) and Highcharts (Free Personal).
D3 allows you to bind arbitrary data to a Document Object Model (DOM), and then apply data-driven transformations to the document. For example, you can use D3 to generate an HTML table from an array of numbers.
RAWGraphs is an open source app built with the goal of making the visualization of complex data easy for everyone. Born as tool for designers and vis geeks, RAWGraphs aims at providing a missing link between spreadsheets and vector graphics editors.
The Google Charts is an extremely simple tool that lets you easily create a chart from some data and embed it in a webpage. You embed the data and formatting parameters in an HTTP request, and Google returns a PNG image of the chart.
vis.js is a dynamic, browser based visualization library. The library is designed to be easy to use, to handle large amounts of dynamic data, and to enable manipulation of and interaction with the data.