Senior Software Engineer, Infrastructure/Platform

Job Description

Job Description

San Francisco, CA · On-site · Full-time Compensation: $250,000–$350,000 + competitive equity (4-year vest)

About the Company

Our client is an applied AI research lab investigating the boundaries and capabilities of AI through novel datasets and experimentation. Its customers are the frontier AI labs — every major foundation-model lab is a client. It's one of the fastest-growing companies in its cohort and well-backed by top-tier investors, with a founding team from top quant firms, big tech, and leading AI research labs.

Founded 2025 · 11–50 people (Series A) · Industry: AI / Data

The Role

As a Senior Software Engineer, Infrastructure and Platform, you'll design and build the core infrastructure powering the client's data generation, evaluation, and agentic systems — the shared platforms that let engineers and research teams run large-scale human-in-the-loop workflows, evaluation harnesses, and automated data pipelines used to train frontier models.

Tech stack: Python, JavaScript (Node.js / Next.js) · GCP / AWS · message queues / event-driven (Kafka, RabbitMQ, Pub/Sub) · high-throughput async data pipelines · (also Go, Redis, Elasticsearch, Kubernetes).

Requirements

• 5+ years building production distributed systems or platform infrastructure
• Proficiency in Python and/or JavaScript (Node.js/Next.js) or similar backend technologies
• Experience designing and operating systems in cloud environments (GCP or AWS)
• Experience with message queues and event-driven systems (Kafka, RabbitMQ, Pub/Sub, or equivalent)
• Experience with high-throughput data pipelines and asynchronous processing
• A strong understanding of system scalability, performance, and reliability
• Experience owning systems running in production at scale
• A top-tier startup or FAANG-equivalent background is a strong signal of fit

Nice to Haves

• Experience building internal developer platforms or shared infrastructure
• Experience supporting large-scale data-processing pipelines
• Experience with AI infrastructure, LLM evaluation systems, or ML pipelines
• Experience at high-growth startups or scaling early infrastructure
• Experience designing human-in-the-loop or workflow-orchestration systems

Why Join

• Foundational ownership: architect and build the core infrastructure many other engineers and researchers depend on
• Frontier impact: the platforms you build power the data generation, evaluation, and agentic systems used to train frontier AI models
• An architecture-defining seat: work directly with the founding team to define system architecture and engineering best practices
• Backing and trajectory: one of the fastest-growing in its cohort, competitive salary + equity (4-year vest), daily lunch and dinner, gym, health insurance

Details

• Location — San Francisco, CA
• Work policy — On-site
• Compensation — $250,000–$350,000 + competitive equity (4-year vest)
• Visa sponsorship — Available (O-1, OPT)
• Employment type — Full-time