AI cloud startup Modal closed a $750 million Series D on October 14 at a $15.75 billion post-money valuation. On Bloomberg Tech, CEO Eric Bernhardsen put the sandbox product at the center, saying Modal has run more than 3 billion sandboxes and books about $300 million in run-rate revenue from them, with Cognition, Ramp and TypeSafe as customers. The Information's TITV then reported an annualized revenue run rate of $1 billion, up from $300 million in May, with compute rented from 25 cloud vendors. The discussion now turns on how the sandbox figure relates to the larger total, and how much of the business sits outside it.