Sail Research Emerges from Stealth with $80M to Slash AI Agent Inference Costs

What happened

Sail Research came out of stealth on June 25 with $80M in combined seed + Series A at a $450M valuation. The Series A is led by Kleiner Perkins; angels include Alphabet chairman John Hennessy, Intel CEO Lip-Bu Tan, and Together AI's Tri Dao.

Context and impact

Sail targets the fastest-growing inference category — stateful inference for long-running agents (coding sessions, research tasks, recruiting agents) where traditional stateless inference wastes context. The positioning is 'software alternative to custom silicon' — instead of building a chip, radically optimise the serving stack on commodity GPUs.

Details

• Series A lead: Kleiner Perkins; angels: John Hennessy, Lip-Bu Tan, Tri Dao
• Valuation: $450M
• Inference service launched March 2026, already processing trillions of tokens per week
• Specialty: stateful sandbox infra for long-horizon autonomous agents
• Positioned as software alternative to custom inference silicon