We are an international network of cities that partners with local administrations of all sizes and all over the world to assist them in their journey towards digital transformation. We work with our members, partners and independent experts to create sustainable impact for our cities via a minimal technical ground for their digital tools and systems. We call this the Minimal Interoperability Mechanisms or MIMs. We facilitate seamless sharing and re-use of digital, data-driven solutions to avoid vendor lock-in, to reduce innovation costs and improve efficiency, thanks to open standards and APIs (application programming interfaces).