A sandbox hour is one hour of a 1 vCPU / 2 GB RAM cloud development environment — the isolated workspace where your agent builds, runs, and tests your app and serves live previews. Larger environments use proportionally more: a 4 vCPU / 8 GB environment consumes 4 sandbox hours per hour.
Usage is metered by the second, so you only pay for the exact compute you use — there's no hourly rounding. Sandbox hours are pooled across your whole workspace, never charged per seat.
Idle environments are paused automatically, so you only burn time while an agent is actively working or you're using a live preview.