Workflow graphical editor and translator to Nextflow

Abstract* Background The Workflow Description Language (WDL) is an open standard that is widely used for bioinformatics workflows. Due to its declarative nature WDL workflows can be easily presented and edited as graphs. Nextflow is both domain specific language for bioinformatics workflows and a convenient workflow execution engine. Our objective was to develop a tool that allows a user to edit WDL workflows visually as a graph providing synchronisation between its textual and graphical representation. Methods Translation of WDL workflows into Nextflow ones allows usage of both languages with the same execution engine. BioUML platform provides class library for object oriented presentation of most common workflow concepts as well as plugins for workflow visualisation and its graphical editing. Results We have developed a WDL parser that with some limitations maps content of WDL workflows into its object-oriented presentation (model). This model can be visualised and edited as a graph. WDL and Nextflow generators create WDL and Nextflow text from the same model. Conclusions Developed tools are available as a standalone Java program, web server, web service and a plugin for the BioUML platform.