This study examined the effectiveness of a blended cross-tier language teacher development program on designing online video-based pragmatic assessment and its impact on student learning experience. Several stakeholders participated in this study, including 12 preservice and six inservice English-as-a-Foreign-Language (EFL) teachers, four instructional advisors, and 148 secondary school students. Data sources included surveys, individual interviews, focus group interviews, and reflection entries. Relying on the theoretical framework of community of inquiry, data analyses depicted the nature and process of preservice and inservice EFL teacher development, and yet some participating teachers expressed concerns when involved in collaborative professional interaction and assessment design. In terms of student learning experience, the recruited participants overall reported their satisfaction with these language instructors' pragmatic instruction and assessment. Specifically, the majority of students showed a clear preference for the designed technologyenhanced module in spite of the difficulties they came across during the online assessment process. Pedagogical implications and research suggestions are offered based on the major findings and limitations of this study.