Do I need a separate grinder?

It depends on the machine. All-in-ones such as the Breville Barista Express and Ninja Luxe Café include a grinder, which reviewers praise for convenience but note is a compromise versus a dedicated unit. Standalone machines like the Rancilio Silvia Pro X require a separate grinder, and specialist-community consensus is that grinder quality matters as much as the machine for espresso results.