We review some recent results on Sorkin’s spacetime formulation of the entanglement entropy (SSEE) for a free quantum scalar field both in continuum and manifold-like causal sets. The SSEE diamond 2d cylinder has been shown to have Calabrese–Cardy form, while de Sitter Schwarzschild horizons dimensions $$d>2$$ , it matches mode-wise von-Neumann entropy. In these examples is regulated by imposin...