Global SchoolNet (GSN) is a nonprofit 501(c)(3) international educational organization that serves as a clearinghouse for collaborative educational projects, many that are based on the Constructivist Learning model. The organization coordinates projects and competitions focused on humanitarian issues, diplomacy, leadership, innovative teaching, entrepreneurship, STEM, and other academics for schools and youth organizations internationally. About 150,000 educators from 194 countries have registered as members of Global SchoolNet, and about 5.5 million students from 109 countries have participated in GSN projects as of 2020. Global SchoolNet is known for two international competitions, the International CyberFair for students in grades kindergarten through high school, and the U.S. State Department-sponsored Doors to Diplomacy for ages 12 through 19. Global SchoolNet was established in 1984 as Free Educational Mail (FrEdMail) in San Diego, California, where its headquarters still exists.