A minimalist definition of city diplomacy is the involvement of sub-national governments – either cities or provinces – in international affairs. This international involvement has different axes of action that are grouped into three ideas.

The first axis focuses on local development. Local development involves transforming the economic and social reality to address the challenges that governments put on agenda-setting or issues that come up due to external factors, for example, climate change or pandemics that globalization brings. Globalization has impacted the world and the territories critically, so local development is not split out from the internationalization component.

Internationalizing – the second axis – is then the process through which cities and territories engage in the international system through cooperation agreements, promotion of the city and its tangible assets, and especially intangible assets, among the various activities they carry out. As cities become more and more decisive in the production chains in the world, with a strong focus on information and knowledge economy, and at the same time, agglomerate more inhabitants (world urbanization process), cities and metropolises increasingly play a role on the world scene. So they are actors in global governance.

This Global Governance occurs in an environment of multi-layered diplomacy: A macro-layer of political and economic blocs. A Meso-layer corresponding to the bilateral relationship of states and regional sub-blocs. Finally, a Micro-layer, regarding the involvement of cities with agendas that sometimes complement or conflict with traditional actors in international relations.