Yes, the UPPAbaby bassinet is safe for sleeping. UPPAbaby has approved the bassinet, which fits the Vista, Cruz, Ridge (with adapters) and Minu strollers (with adapters), as an overnight sleep solution.
You can use the UPPAbaby bassinet as your newborn's first bassinet for all-day outings, in your home, or while traveling, either on its own or paired with a compatible stroller or UPPAbaby's wooden stand.
UPPAbaby advises a few things when using the bassinet for a sleep solution, including that you should only use the included mattress and mattress cover, and never add pillows or additional soft bedding inside the bassinet. While using the bassinet for extended sleep, the canopy should be raised and locked in its upright, open position.