A single software or, more specifically, a single database, allows for a seamless flow of data and communication between tools. This is the only way to achieve true HR and payroll automation. It also eliminates the need for hopping between apps that require different logins, reentering data into each and the security risks that come with multiple entry points. Be cautious of providers that claim to have a single software or database but are a patchwork of several systems designed to appear as one.