Modal crosses $1B annualized run rate in $750M Series D round

Key points

• Series D valued Modal at $15.75B, led by Accel, per the company's announcement.
• Since its Series C, Modal's usage has tripled and revenue has grown more than 15x year over year.
• Its Sandboxes product reportedly reached a $300M run rate on its own, with close to 3 billion sandboxes spun up.
• Sandboxes serve background agents, reinforcement learning and vibecoding platforms, and reportedly scale to a million concurrent.

Why it matters for marketers: Content teams selling into agent builders can point to Modal's reported sandbox traction as evidence of demand for agent execution infrastructure.