Sail Research announced that it has raised $80 million in Seed and Series A funding at a $450 million valuation.
The company is building infrastructure purpose-built for long-horizon AI agents. The Series A round was led by Kleiner Perkins, and the Seed round was led by Sequoia.
Additional investors included Redpoint Ventures, Theory Ventures, Vine Ventures, CRV, A*, and Abstract Ventures. Angel investors included John Hennessy, chairman of Alphabet; Lip-Bu Tan, CEO of Intel; and Tri Dao, Chief Scientist at Together AI.
Sail Research is focused on the next generation of AI agents that can work autonomously on complex tasks over hours or days. The company said current infrastructure was largely designed for short, prompt-based interactions rather than long-running agent workloads.
The company said agents are constrained by compute, context, rate limits, and cost ceilings across platforms that were not designed for long-horizon use.
Sail’s platform has two core components. The first is an inference stack rebuilt around throughput and efficiency for agents that may spend billions of tokens on a single task. The second is Sailboxes, a sandbox environment designed to run for hours or days while charging only for time agents are actively doing work.
The company said its efficiency advantage comes from proprietary infrastructure optimizations, deep customization of open-source inference engines, intelligent workload distribution across providers, and the use of underutilized compute.
In a recent benchmark, Sail said its inference topped BrowseComp-Plus, achieving 90.72% accuracy at up to 10 times lower cost than leading alternatives.
Sail’s infrastructure is already supporting AI-driven workflows at companies including Parallel Web Systems, Jack and Jill, and Detail.dev.
The company’s API is compatible with existing OpenAI-based workflows and supports leading open-source models including DeepSeek, Gemma, GLM, Kimi, and Nemotron.
Sail Research was co-founded by CEO Neil Movva and CTO Samir Menon. Movva previously worked at NVIDIA, Apple, and Together AI, while Menon previously built large-scale systems at Apple.
KEY QUOTES:
“Sail exists to make intelligence abundant. Every decision we make, from the chip level to the API, is about giving teams the tokens, the scale, and the runtime to build agents without limits.”
Neil Movva, Co-Founder and CEO of Sail
“Most inference infrastructure was designed to minimize latency on a single request, but that’s the wrong optimization for agents, which need to sustain throughput across thousands of concurrent calls over hours. We’ve rebuilt the stack around that constraint, and the efficiency gains compound across every layer.”
Samir Menon, Co-Founder and CTO of Sail
“The infrastructure layer for the agent era is one of the most important bets in AI right now, and Neil and Samir are exactly the founders to build it. They bring a rare combination of deep compute expertise and systems rigor that only comes from having built at the limits of scale. Together, they’re building the defining inference platform for long-horizon agents.”
Aditya Naganath, Partner at Kleiner Perkins
“We and Sail share a belief that background agents are about to do far more useful work. Getting there takes efficient, scalable inference paired with the highest-quality context, including from the web. Sail is building the inference side of that, and we’re glad to be aligned on where this is going.”
Travers Nisbet, Co-Founder of Parallel
“Building on Sail lets us ship long-horizon agents with great economics. Trillions of tokens and counting, we’re happy customers.”
Dan Robinson, CEO of Detail.dev