Crowdfunding is the practice of funding a project or venture by raising money from a large number of people, typically via the internet. Crowdfunding is a form of crowdsourcing and alternative finance. In 2015, over US$ 34 billion was raised worldwide by crowdfunding.

Although similar concepts can also be executed through mail-order subscriptions, benefit events, and other methods, the term crowdfunding refers to internet-mediated registries.This modern crowdfunding model is generally based on three types of actors – the project initiator who proposes the idea or project to be funded, individuals or groups who support the idea, and a moderating organization (the “platform”) that brings the parties together to launch the idea.

Crowdfunding has been used to fund a wide range of for-profit, entrepreneurial ventures such as artistic and creative projects,medical expenses, travel, and community-oriented social entrepreneurship projects. Although crowdfunding has been suggested to be highly linked to sustainability, empirical validation has shown that sustainability plays only a fractional role in crowdfunding. Its use has also been criticized for funding quackery , especially costly and fraudulent cancer treatments.