D3 (or D3.js) is a free, open-source JavaScript library for visualizing data. Its low-level approach built on web standards offers unparalleled flexibility in authoring dynamic, data-driven graphics. For more than a decade D3 has powered groundbreaking and award-winning visualizations, become a foundational building block of higher-level chart libraries, and fostered a vibrant community of data practitioners around the world. D3 “slingshotted the field into growth, diversification and creativity that has been unprecedented” and “changed how millions of data visualizations are created across newsrooms, websites, and personal portfolios,” remarked the Information is Beautiful 2022 Test of Time Award. The IEEE VIS 2021 Test of Time Award noted, “By creating a framework that was compelling and easy for web developers to use to author interactive visualizations, the authors have undeniably helped to bring data visualization to the mainstream. [D3] is a cornerstone contribution to this conference specifically and more generally to the success of our field as a whole.” D3 was created by Mike Bostock in 2011. Mike co-authored the D3 paper with Jeff Heer and Vadim Ogievetsky at Stanford. Jason Davies made major contributions to D3 from 2011 to 2013, most notably to D3’s geographic projection system. Philippe Rivière has been a major contributor to D3 and its documentation since 2016. Over the years, countless kind individuals have contributed to D3 by sharing code and ideas, by teaching and answering questions, and by bringing people together to further the practice of visualization. Mike and Philippe now maintain D3 and Observable Plot at Observable.