Projekt DEAL, an initiative commissioned by the Alliance of German Science Organizations, and Springer Nature have completed the world's largest transformative Open Access agreement. Springer Nature publishes about 17% of all scientific articles published annually at German scientific institutions. These publications are now globally freely available, visible, and legally secure via the new Open Access contract. More than 900 German institutions are eligible to participate in the agreement between Springer Nature and Projekt DEAL, meaning that corresponding authors affiliated with these institutions are eligible to publish their articles open access without being invoiced by Springer Nature. This will substantially and permanently improve access to Springer Nature content for the entire German research landscape.