This chapter addresses local initiatives supported by city governments. It introduces urban platform intermediaries (UPIs) as strategic intermediaries enhancing the realization of sustainable energy aims, and it investigates their roles, actions and organizational position. With socio-technical transition as a starting point, a reflective framework to evaluate UPIs is developed, using two contrasting examples in Amsterdam: NewNRG and its spin-off ‘We’re Getting Chickens’ and Amsterdam Smart City and its project City-Zen. Amsterdam has high ambitions with regard to sustainable energy, but which is complicated by the need for degasification of the housing stock. With similar tasks of connecting actors, the initiatives show substantial differences in position. NewNRG has a bottom-up, grassroots character, and attracts mostly newcomers; however, it struggles to attract funding and organizational stability. ‘Established’ Amsterdam Smart City and its incumbent actors have the potential to upscale inventions and make innovations grow, but they are unlikely to initiate radical activities.