Ultraviolet observations probe the bulk of the bolometric luminosity of the hottest supernovae, including energetic explosions and interactions between the ejecta and circumstellar material.  Historically, these observations have been limited due to the need for space-based telescopes.  With the Neil Gehrels Swift Observatory's UltraViolet Optical Telescope we have been able to observe hundreds of supernovae of all types.  I will show the diverse behavior of supernovae in the ultraviolet, especially the UV-bright superluminous and type IIn supernovae, and the prospects for observing them at higher redshifts.