Startups are the fuel of the innovative drive we find in cities. New goods and services are continuously introduced to offer digital and sustainable solutions to all urban verticals, such as Smart Mobility, Smart Utilities and Smart Services for the citizens. Despite the primary role of these businesses in the implementation of urban projects, there is still little literature on the subject. For this reason, the objectives of the thesis are: (i) to establish a well-structured framework that gives proper recognition to the startup activities in urban development; (ii) to build the first database collecting the national and international experiences. In particular, the work could be structured in the following sections: 1. research on the most innovative vertical areas in which startups are active; 2. review of the success stories; 3. collection of data for the first database on Italian and international Smart Cities startups.