This study contributes knowledge about how a digital badge system integrated into an online, subject-matter-specific, and competency-based professional development (PD) program affected teachers' experiences with and perceptions of the program activities. The report presents findings from a one-year exploratory study of an online PD program, and accompanying digital badge system, called "Who Built America Badges: Common Core Professional Development from the American Social History Project." The American Social History Project (ASHP), a well-established history and social studies professional development provider in New York City, created the system to make its PD program available to a national audience of middle and high school teachers. The program's main goal is to help teachers develop new instructional routines that build students' reading and writing practices that are specific to the domain of history, as well as their historical reasoning skills. The "WBA" program accommodates teachers' immediate practical needs for classroom-ready materials, while promoting long-term development of instructional practices that align to ASHP's vision of a master history teacher's practices. The following are appended: (1) Builder Badge Criteria; (2) Teacher Profile Page Screenshot; (3) Submission Form Example; and (4) Interview Protocol.