Miniaturization of biological and chemical assays in lab-on-a-chip systems is a highly topical field of research. Full custom centric design of droplet-based microfluidic lab-on-a-chip systems leads to a high system integration level and design complexity. We report on a software toolkit for modeling droplet traffic and processing for even complex microfluidic networks. As a result, the advantages of lab-on-a-chip systems will be accessible for more people through the easy, versatile and efficient transformation of even complicated laboratory workflows to compact and easy to use lab-on-a-chip applications.