Microsoft OneDrive is a file-hosting service operated by Microsoft. First released as SkyDrive in August 2007, it allows registered users to store, share, back-up and synchronize their files. OneDrive also works as the storage backend of the web version of Microsoft 365. OneDrive offers 5 gigabytes of storage space free of charge, with 100 GB, 1 TB, and 6 TB storage options available, either separately or with Microsoft 365 subscriptions.