Software Engineer, Platform

Join a founding developer team building platform infrastructure for an AI evaluation platform. Build and scale backend services for an AI gateway that unifies model providers. Solve streaming problems, build observability, authentication, rate limiting, and integrate with evaluation platform. Work directly with founders and early customers. This role is hands-on, in San Francisco onsite five days a week. The company is a fast-growing startup redefining how AI model performance is measured.

5+ years of professional software engineering experience with backend services, distributed systems, or developer-facing platforms. Strong Golang experience required. Experience designing reliable APIs, service integrations, or gateway/proxy-style systems. For senior: track record of owning backend functionality end-to-end. For staff: extensive experience and technical leadership. Cloud experience helpful. Must work onsite in San Francisco five days per week.