The transition in welfare states from compensatory to service-oriented models also implies a shift of the locus of action from the state to local administrations. Cities in particular seek space within national bounds to devise their own policy solutions targeted to city-specific needs as a more responsive government layer, with the prospect of providing more targeted service provision on the basis of locality and proximity principles. Whether such social innovation potential is met depends on scope conditions, such as the learning environment, the design of the decentralisation and the capacity of cities to scale up smaller projects. In this paper, we trace the policy process around local social investment innovations in Amsterdam across three domains: addressing teacher shortages, combatting energy poverty and integrating the long-term unemployed into the labour market. In each of the domains, Amsterdam emerged as a frontrunner and innovator, instigating broader change. The city is at the frontier of societal change and acts as ‘a stopgap’, filling gaps left by national policy default. Overall, the case of Amsterdam shows the importance in adopting a multi-level perspective in studying new dynamics in welfare state transitions.