Sustainable software engineering (SSE) is the practice of minimisingthe environmental cost of software. It is an emerging discipline at the intersection of climate science, software practices and architecture, electricity markets, hardware, and data centre design. In this report, we’ll look at which developers are involved in building sustainable software and which SSE principles are most commonly utilised. We’ll investigate how developers’ experience levels, location, and the size of the organisation they work for –amongst other factors –affect the rate at which they utilise SSE and which principles they most often adopt. Later, we’ll take a closer look at what motivates developers to utilise SSE principles, as well as which challenges they face in doing so. We’ll demonstrate how developers’ motivations and challenges change based on several different factors, such as their experience levels.