A compostable capsule for making infusion or soluble beverages is provided. The compostable capsule has a cup in which an inner volume is defined. At least one substance to be infused or dissolved is contained in the inner volume. The cup has a bottom having an outlet opening, an inlet opening closed by a cover, and an inner base. The compostable capsule has an at least partially flexible sealing disc fastened on the inner base of the cup to ensure, with the cover, a seal of the inner volume. The cup, the cover and the sealing disc are made of a compostable material. Opening of the compostable capsule for outflow of a beverage is determined by an at least partial deformation of the sealing disc.