User Participation through WhatsApp – Mobile Instant Messaging as a Medium for Distributed Co-design

User participation is often time and resource intensive for both the designers and participants. This is especially problematic in cases where designers and users are not co-located and have to travel to participatory meetings. Distributed co-design through remote participation technologies has been hoped to alleviate these issues. However, distributed co-design has its own issues, such as requirement of an access to suitable technology independently by the participants. In this paper we present three cases where distributed co-design has been mediated through WhatsApp\textsuperscript{TM}, the currently most wide-spread mobile instant messaging app. Our lessons learned from these projects indicate that mobile instant messaging has potential in distributed co-design, and the continuous access to communication channels can enable detailed discussions between the designers and the participants. To summarise our findings, we present a framework to help future academics and practitioners to plan and implement (part of) their co-design process in mobile instant messaging services.