The rhetoric that surrounds the Internet of Things (IoT) contends it will bring about utopian transformative change throughout society, particularly in regards to sustainability. Little discourse however, recognises the intrinsically unsustainable nature of IoT devices themselves. Under a façade of innovation, the IoT is a breeding ground for superfluous, novelty ‘gizmo’ products whose design incorporates environmentally damaging modes of manufacture, consumption and disposal. To bring attention to this growing unsustainable design culture, we have produced a manifesto entitled Spimes Not Things: A Design Manifesto for A Sustainable Internet of Things. It is the synthesis of a practice-led research project which explores Sterling’s spimes concept using Design Fiction methods, as part of a Research through Design approach. This paper outlines the manifesto’s creation, its theoretical foundations and its intentions. The manifesto is the first step towards the reframing of design practices that will contribute to a more sustainable IoT product paradigm.