RT Journal A1 Bray, Simon A1 Chilton, John A1 Bernt, Matthias A1 Soranzo, Nicola A1 van den Beek, Marius A1 Batut, Bérénice A1 Rasche, Helena A1 Čech, Martin A1 Cock, Peter J.A. A1 Grüning, Björn A1 Nekrutenko, Anton T1 The Planemo toolkit for developing, deploying, and executing scientific data analyses in Galaxy and beyond JF Genome Research JO Genome Research YR 2023 FD February 01 VO 33 IS 2 SP 261 OP 268 DO 10.1101/gr.276963.122 UL http://genome.cshlp.org/content/33/2/261.abstract AB There are thousands of well-maintained high-quality open-source software utilities for all aspects of scientific data analysis. For more than a decade, the Galaxy Project has been providing computational infrastructure and a unified user interface for these tools to make them accessible to a wide range of researchers. To streamline the process of integrating tools and constructing workflows as much as possible, we have developed Planemo, a software development kit for tool and workflow developers and Galaxy power users. Here we outline Planemo's implementation and describe its broad range of functionality for designing, testing, and executing Galaxy tools, workflows, and training material. In addition, we discuss the philosophy underlying Galaxy tool and workflow development, and how Planemo encourages the use of development best practices, such as test-driven development, by its users, including those who are not professional software developers.