Flow Engineering has raised a $50 million Series B at a $750 million valuation, in a round co-led by Antonio Gracias of Valar Equity Partners and Gavin Baker of Atreides Management. Sequoia Capital, which led Flow’s Series A, also participated, while former Sequoia partner Roelof Botha invested personally and joined the company’s board. The three-year-old, San Francisco-based startup develops AI tools for hardware design, including agents that align CAD drawings with product requirements, simulation results and other testing. Flow’s platform supports validation and verification by linking requirements, designs, simulations and test results in a systems graph, helping engineers identify conflicts when designs change. Its customers include Anduril, Rivian, Joby Aviation, General Motors PPU, RV Tech and Stoke Space.