Modal Labs raises $750M at $15.75B valuation

AI infrastructure startup Modal Labs has raised $750 million in a Series D round led by Accel, with participation from Kleiner Perkins and existing investors. The company is now valued at $15.75 billion, more than triple its May 2026 valuation. Modal says its annualized revenue has also more than tripled since May to over $1 billion. Nearly a third of revenue comes from Sandboxes, a hosted container service optimized for AI workloads and agents. Modal plans to use the new funding to develop services focused on reinforcement learning and post-training.