Developer engagement in open-source software’s green transition

Abstract Software development plays a central role in digital sustainability, yet developers’ role and engagement remains understudied. Here we analyse nearly a decade of developer discussions available on the code repository Github on Ethereum, a widely used open-source blockchain platform. Using topic modelling, with interpretation supported by large language models and a sustainability framework for software systems, we trace how economic, environmental, social, individual, and technical sustainability themes emerge and evolve over time. We find that sustainability awareness, particularly related to energy efficiency and cost, intensifies during key events such as the transition from proof-of-work to proof-of-stake consensus, which substantially reduced energy use. We identify influential contributors and thematic specialisation, providing a transferable framework for understanding sustainability in emerging developer communities. These findings highlight the role of developer discourse in shaping sustainable software ecosystems and integrating sustainability into open-source development.