Software engineering for ‘social good’ is an area receiving growing interest in recent years. Software is increasingly seen as a way to promote positive social change: this includes initiatives such as Code for America and events such as hackathons, which strive to build innovative software solutions with a social conscience. From a software engineering perspective, existing software processes do not always match the needs of these social software projects, which are primarily aimed at social change and often involve vulnerable communities. In this paper, we argue for new software processes that combine elements of agile, iterative development with principles drawn from action research and participatory design. The former allow social software projects to be built quickly with limited resources; the latter allow for a proper understanding of the social context and vulnerable user groups. The paper describes Speedplay, a software development management framework integrating these approaches, and illustrates its use in a real social innovation case study.