Supply Chain report is produced to shed light on the patterns and practices associated with open source software development. We began collecting data for our 2019 report from the moment our 2018 report was published. The report is made possible thanks to a tremendous effort put forth by many team members at Sonatype, including: Derek Weeks, Matt Howard, Joel Orlina, Bruce Mayhew, Gazi Mahmud, Dariush Griffin, Mike Hansen, Brian Fox, Ilkka Turunen, Elissa Walters, Daniel Sauble, Adam Cazzolla, Alex Metry, Andrew Stein, Ken Duck, Kevin Hayen, Kevin Witten, Shade Solon, Alvin Gunkel, and Aaron Massey. We would also like to offer thanks for contributions big and small from: Hasan Yasar (Carnegie Mellon University Software Engineering Institute), Laurie Voss (npm), Brian Dawson (CloudBees), DJ Schleen (Aetna CVS), Nichole Schimanski (Galois) and Eric Davis (Galois), James Wickett and others across the DevOps and open source development community. A very special thanks goes out to Melissa Schmidt who created the incredible design for this year’s report. Finally, we could not have produced this report with- out the amazing contributions and countless hours of deep analysis from our research partners Gene Kim from IT Revolution and Dr. Stephen Magill, Principal Scientist at Galois & CEO of MuseDev. About the Analysis The authors have taken great care to present statis- tically significant sample sizes with regard to compo- nent versions, downloads, vulnerability counts, and other data surfaced in this year’s report. Specifically to Chapter 3, all reported differences are statistically significant (p < 0.05) according to a Mann–Whitney U test. While Sonatype has direct access to primary data for Java, JavaScript, Python, .NET and other component formats, we also reference third-party data sources as documented. 46 2019 STATE OF THE SOFTWARE SUPPLY CHAIN REPORT