Senior Platform Engineer — Go, APIs & AI Evaluation

Arena Intelligence, Inc.; San Francisco (CA); On-site; USD 140,000 - 210,000; Full time

Benefits offered by this job

Equity

Health benefits

Competitive salary

Cutting-edge AI work

Job summary

Arena Intelligence, Inc. is building core infrastructure for evaluating AI models in real-world scenarios. We are seeking a Software Engineer - Platform to ship low-latency APIs, scalable runtimes, and robust gateways that support live evaluation systems at scale.

You'll work with researchers and product leadership as an early infra team member. The role is hands-on, with zero-to-one work early on and scale-it-up later, in a fast-paced, collaborative environment based in San Francisco.

Qualifications

• ~5+ years of backend engineering experience with distributed systems, infrastructure, or developer-facing platforms.
• Strong proficiency in Go, the primary backend language for this role.
• Experience with LLM provider APIs (OpenAI, Anthropic, Google, etc.) and streaming/token-management challenges.
• Product-oriented mindset focused on developer experience of APIs.
• Comfort with ambiguity in a startup environment.

Responsibilities

• Build API-based products from the ground up with low-latency, reliable endpoints for leaderboards, models, and arenas.
• Tackle streaming challenges like SSE and mid-stream fallback with robust normalization.
• Ship enterprise-grade infrastructure including rate limiting, auth, usage metering, and audit logging.
• Develop deep observability with tracing, latency metrics, and real-time dashboards.
• Collaborate with research to turn ideas into full-featured products; avoid data labeling tasks.
• Contribute to backend work across Leaderboards and Evals platforms to unify data architectures.

Skills

Go

Distributed systems

Backend engineering

API design

Product mindset

Tools

Kubernetes

Terraform

PostgreSQL

Redis

Job description

Arena Intelligence, Inc. is building core infrastructure for evaluating AI models in real-world scenarios. We are seeking a Software Engineer - Platform to ship low-latency APIs, scalable runtimes, and robust gateways that support live evaluation systems at scale.

You'll work with researchers and product leadership as an early infra team member. The role is hands-on, with zero-to-one work early on and scale-it-up later, in a fast-paced, collaborative environment based in San Francisco.