What is Microsoft Exchange?

Microsoft Exchange – also known as Microsoft Exchange Server – is a mail server for Windows developed by Microsoft. It includes a calendaring software and a contact manager.

Exchange is available as an installation package for Windows Server – or included in some Windows Server editions – and as a cloud solution named Exchange Online.

What is ESXi?

ESXi is a bare metal hypervisor – also known as Type-1 hypervisor – developed by VMware.

In a nutshell, it’s an operating system with an integrated hypervisor.

ESXi is part of the VMware vSphere platform.