The purpose of the article is to determine the role of co-financing technologies (crowdfunding, fundraising) under the conditions of war and post-war reconstruction. The basis of the study is the case analysis of international support to Ukraine to counter Russian aggression. The central issue of the article is to clarify the acceptability, effectiveness, as well as problems of applying co-financing technologies to solve the problems caused by the war. The existing global experience of using co-financing technologies during wars was studied, the peculiarities of the Ukrainian case were revealed. The advantages, problems and risks of using crowdfunding and fundraising during a full-scale war are identified. The motivation of the public of other states to co-finance the solution or mitigation of the problems caused by Russia’s aggression on the territory of Ukraine is ascertained. The research is based on the analysis of projects supporting Ukraine and Ukrainians during the days of the Russian aggression on leading crowdfunding platforms, as well as through fundraising. Crowdfunding and fundraising are considered as forms of remote involvement, elements of digital action repertoires, which are used by the democratic public from all over the world (and in the case of Ukraine, also by government institutions) to convey their position on war and mitigate its consequences. It is concluded that modern technologies of cofinancing enable remote involvement of citizens of different states in international conflicts and humanitarian crises caused by these conflicts and wars. The dependence of the use of crowdfunding and fundraising technologies on the type of political regime and the characteristics of political culture of the dominant part of the population is proven.