The creation and adoption of a software ecosystem is becoming increasingly pervasive, leading to new research and management challenges. Several companies are platformizing successful products and opening these products up for outside innovation where customers expect to be actively involved in the shaping of the technology they use. This also leads to new opportunities and challenges regarding new business models, open innovation, collaborative development, strategic planning, and coordination of multiple platforms. IWSECO and WEA aim to further increase the body of knowledge in software ecosystems by providing a forum to exchange ideas and discuss the most recent innovations, trends and experiences in the field. It aims to build and shape the community of leading practitioners and research experts by providing a forum for the exchange of research results and industrial practice in software ecosystems. By co-locating both, IWSECO and WEA we aim at attracting and involving interested participants from the larger European software engineering community in an early stage of shaping software ecosystem research and community building. The co-located workshops will be a venue for practitioners and researchers to share experience and lessons learned; with a particular focus on architecture, as the ecosystem architecture can actually determine the success or failure of software ecosystems as a whole.