@dhruv477 while there has been a number of requests for this, the complexity of the task is such that it hasn't been built by anyone yet. I think we should really invest some time into building a new Vega transformation that wraps d3's Sankey logic. Once done, multilevel sankey graphs will become far easier. But as always with the open source - someone has to actually spend time creating it and submitting a pull request. Hopefully there will either be a volunteer soonish, or I will try to find some time to wrap my brain around it, or we could convince the Vega team to build it (I think there is a Vega issue for it somewhere)... So... I'm still hopeful 