Moss
Moss is a YC Fall 2025 (F25) company. Based in San Mateo, CA, USA. Team of 3.
About Moss
Summary
Moss builds a real-time semantic search runtime for voice agents, copilots, and chat interfaces, replacing cloud-based vector database retrieval pipelines that introduce lag. The engine runs natively in browsers, on edge devices, and on servers via a Rust and WebAssembly vector index, returning results in under 10 milliseconds without external network hops. Teams building conversational and multimodal AI products use Moss to eliminate the retrieval bottleneck that breaks the illusion of a responsive, intelligent agent.
Business model
A free tier plus paid plans, as shown by the "Start Free" entry point on the website.
Go-to-market
Moss targets developers and product teams building voice AI, copilots, and in-app search, acquired through self-serve signup alongside a direct path to speak with an engineer for production deployments.
From the Y Combinator listing
Real-time semantic search for Conversational AI
Moss is building the real-time semantic search runtime for conversational and multimodal AI. Our system enables voice agents, copilots, and chat interfaces to retrieve, reason, and respond in sub-10 ms, delivering the responsiveness that makes AI interactions feel truly natural. If you’ve ever built a conversational or voice AI product, you’ve felt the lag. That moment when an agent pauses and the illusion of intelligence breaks. The bottleneck is almost always retrieval. Each query hops across networks and databases, adding delay and cost. Moss eliminates that gap by keeping retrieval close to where the agent runs. Moss runs natively across browsers, mobile devices, and servers with an optimized vector index built in Rust and WebAssembly. It enables teams to build AI products that feel instant, contextual, and adaptive. The experiences that sustain engagement and unlock new kinds of interaction. For our customers, this translates into tangible business value: stronger user retention, higher conversion, and entirely new product categories made possible by real-time understanding. Moss is already powering production pilots across voice AI and developer platforms, achieving sub-10 ms retrieval and 70–90% token savings compared to traditional pipelines.
Facts
- B2B / B2B
- San Mateo, CA, USA
- 3
- Active
- Early
Founders (2)
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