
SF Tensor
SF Tensor is a YC Fall 2025 (F25) company. Team of 3.
About SF Tensor
Summary
SF Tensor builds infrastructure that lets AI researchers train models without managing the underlying compute stack. Its platform spans two layers: a managed cloud that sources GPUs across providers and handles spot preemption, and an automatic kernel optimizer that tunes training code to the target hardware without requiring hand-written CUDA. The work it replaces is weeks spent by researchers configuring distributed systems, debugging infrastructure, and writing hardware-specific kernels instead of doing research.
Business model
Compute cost savings imply usage-based or platform fees, but the sources do not specify how SF Tensor charges customers.
Go-to-market
AI labs and research teams are the buyers; the platform targets teams already writing PyTorch code who want to run on non-NVIDIA hardware without software friction.
From the Y Combinator listing
Infrastructure for AI labs to focus on research.
AI researchers should be pushing the boundaries of what's possible with new architectures and training methods. Instead, they waste weeks configuring cloud infrastructure, debugging distributed systems, and optimizing their GPU code. We know because we lived it: While training our own models across thousands of GPUs earlier this year, we spent more time fighting our infrastructure than doing actual research. That why we're building two things. First, Elastic Cloud: a managed platform that automatically finds the cheapest GPUs across all providers, handles spot instance preemption, and cuts compute costs by up to 80%. Second, automatic kernel optimization that makes training code run faster by modeling hardware topology, often beating hand-tuned implementations. The problem is that getting high performance across different hardware is genuinely hard. NVIDIA's CUDA moat exists because writing fast kernels requires deep expertise. Most teams either accept vendor lock-in or hire expensive kernel engineers. Our goal is to break the CUDA moat. The compute bottleneck is the biggest constraint on AI progress. NVIDIA can't manufacture enough GPUs, and their monopoly keeps prices astronomical. Meanwhile, AMD, Google, and Amazon are shipping capable alternative hardware that nobody uses because the software is too hard. We're breaking that moat. If we succeed, anyone will be able to train state-of-the-art models without thinking past their PyTorch code.
Facts
- B2B / B2B -> Infrastructure
- 3
- Active
- Early
Founders (3)
- Ben Koska
- Luk Koska
- Tom Koska
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