Modal's Series C: Raising $355M at a $4.65B valuation

Modal has raised $355M in a Series C round at a $4.65B valuation, led by General Catalyst and Redpoint. The company reports fivefold growth since its Series B and over $300M in annualized revenue. Modal positions itself as a cloud platform purpose-built for AI workloads, offering elastic GPU compute, isolated sandboxes for agent runtimes, and low-latency inference. Key use cases include fine-tuning and serving open-weight models, reinforcement learning pipelines, and agentic code execution — with over 1 billion sandboxes launched to date. Future plans include deeper investment in the inference stack (Flash Attention, vLLM, SGLang), collapsing the training-inference loop for RL, and expanding sandbox capabilities with granular RBAC for agent workflows.