Cumulus Labs
The Fastest Multimodal Inference OS
Cumulus Labs at a glance
- Y Combinator batch
- Winter 2026
- Status
- Active
- Industry
- B2B
- Team size
- 2 people
- Location
- Not recorded
- Website
- Not recorded
Every field above comes from the Y Combinator company record. Nothing is estimated.
About Cumulus Labs
Cumulus Labs lets engineering teams ship AI in production without needing a dedicated ML platform team. Right now, companies building AI products are forced to stitch together separate vendors for routing, observability, evaluation, fine-tuning, and inference. This fragmented approach is brittle, expensive, and is a common reason enterprises fail with AI. We replace that entire stack with a single unified platform. Developers can keep their existing code while instantly upgrading to a unified platform that handles routing, semantic caching, continuous shadow evaluation, simulated data, and one-click fine-tuning. Behind the platform is Ion, our proprietary inference engine running on a custom NVIDIA Grace GPU fleet. Ion uses in-house custom GPU kernels to deliver 30 to 50 percent more throughput than standard vLLM or SGLang, giving our customers SOTA inference economics.