Baseten, the California-based AI inference platform, closed a $1.5 billion Series F round at a $13 billion valuation, the company announced on its blog on Monday. The round was led by Altimeter Capital, Conviction Partners, and Spark Capital, co-led by Sands Capital and Wellington Management, with participation from Battery Ventures, Blackbird, D.E. Shaw Ventures, Durable Capital Partners, Greylock, IVP, Verified Capital, and 01A.

This is Baseten’s fourth capital raise in 18 months, according to Prism News. The company raised a $75 million Series C in February 2025, a $150 million Series D at a $2.15 billion valuation in September 2025, and a $300 million Series E at a $5 billion valuation in January 2026. The new round represents a 2.6x valuation step-up in five months.

20x Revenue, 40x Volume

Over the past year, Baseten’s revenue grew 20x and inference volume increased 40x, according to the company’s announcement. The growth reflects a market shift from training large models to running them efficiently in production. Baseten positions itself as a lower-cost alternative to API providers like OpenAI and Anthropic, emphasizing speed, reliability, and operational cost savings.

The company’s customer roster spans coding, productivity, legal, health, and business software: Cursor, Notion, Lovable, Harvey, HubSpot, OpenEvidence, Abridge, Decagon, and Parallel. These are companies where AI intelligence is embedded directly into the product experience, not bolted on as a feature.

The Inference Thesis

Baseten’s pitch is that open-weight models have become strong enough for enterprises to use as serious alternatives to closed APIs. The company’s blog cited Satya Nadella’s recent comments that “durable advantage will come from the learning systems companies build around their own data, judgment, workflows, and feedback loops.”

The platform supports dedicated inference for high-scale workloads, pre-optimized model APIs, and training tools that connect directly to deployment. It offers SOC 2 Type II certification, HIPAA- and GDPR-compliant deployment options, and dedicated, self-hosted, and hybrid setups, according to Prism News.

Baseten said it will use the funding to expand computing capacity, software, and hiring.

The Infrastructure Layer Bet

Founded in 2019 by Australians Tuhin Srivastava, Amir Haghighat, and Philip Howes, Baseten has been repriced aggressively as investor appetite for AI infrastructure has expanded. The company describes its work as embedding researchers and engineers with customers to post-train and optimize specialized models, then serving those models with production-grade performance.

The $1.5 billion raise lands as multiple inference-focused companies compete for the infrastructure layer beneath foundation models. For agent builders running autonomous, multi-step workloads, per-token inference costs compound quickly. A dedicated inference layer that optimizes for latency and cost at scale is a prerequisite for making autonomous agents economically viable.