Baseten is closing a $1.5 billion dual-tiered funding round at valuations between $11 billion and $13 billion, up from $5 billion just five months ago. The AI inference infrastructure startup tripled its annualized revenue run-rate from $200 million to $600 million in a single quarter, with customers including Cursor, Mercor, and OpenEvidence reporting up to 30% cost savings over closed-source APIs.