Code/Astro is a week-long astronomy software development workshop motivated by the growing usage of open-source software in astronomical research. The goal of this program is to teach participants fundamental software engineering skills and best practices for building sustainable open-source packages for astronomy applications. During the workshop, participants will obtain hands-on experience with software engineering by developing a small software package from scratch. The workshop will also serve as a networking and career development opportunity. The workshop is free and open to folks at all career levels. Code/Astro is made possible thanks to support by the Heising-Simons Foundation.