Riften builds model routing, evaluations, private models, and training environments for AI labs, AI-native companies, and enterprises. We help teams choose models for their workloads, evaluate how they perform, and build private models around company-specific work. We’re also developing coding environments where agents learn through backend engineering tasks.
The company was founded by Carl Stauffer. It is part of YC Summer 2026. It is based in San Francisco, CA, USA.