Staff Software Engineer

About the Role We're a Y Combinator–backed AI/ML infrastructure startup building reinforcement learning environments that train AI models to perform complex, expert-level tasks. Our small, high-velocity team is tackling hard problems at the frontier of AI research and development — and we're looking for a Staff Software Engineer to help shape the technical foundation that lets us scale. In this role, you'll drive architecture and design decisions across core systems, mentor engineers throughout the organization, and collaborate directly with product and engineering leadership. You'll be a hands-on technical leader who ships production-quality code and raises the bar for the entire team. Work arrangement: Hybrid — Los Angeles, CA (also open to New York City or San Francisco). Visa sponsorship is not available. What You'll Do Lead the architecture and design of scalable, high-impact systems and services. Implement and ship production-quality code that balances performance, observability, and maintainability. Drive system reliability and performance improvements through monitoring, incident response, and remediation. Mentor and coach engineers across the organization to improve engineering practices and support technical growth. Collaborate with product, design, and cross-functional teams to translate product needs into robust technical solutions. Establish and promote best practices for testing, code review, and deployment workflows. Influence the technical roadmap and make thoughtful trade-offs aligned with business and operational goals. What We're Looking For Must-haves: 8+ years of professional software engineering experience, with several years in senior or lead technical roles. Proven track record leading architecture decisions across multiple engineering teams. Extensive experience designing and operating large-scale distributed systems and backend platforms. Production experience delivering backend services in cloud environments (AWS, GCP, or Azure), including containerized applications with Docker and Kubernetes. Hands-on experience with CI/CD pipelines and modern deployment workflows. Proficiency in at least one backend programming language: Python, Go, Java, or Node.js. Strong computer science fundamentals — algorithms, data structures, and system design. Demonstrated ability to mentor engineers, lead technical discussions, and influence cross-functional stakeholders. Nice to have: Experience with relational and NoSQL databases and data modeling. Familiarity with observability and monitoring tooling (e.g., Prometheus, Grafana, OpenTelemetry). Experience with event-driven architectures and streaming systems (e.g., Kafka, RabbitMQ). Background in AI/ML infrastructure or platform engineering. Compensation & Benefits Compensation details were not provided for this listing. Expect early-stage startup equity and a competitive salary commensurate with Staff-level experience. Location This is a hybrid role based primarily in Los Angeles, CA . Candidates in New York City or San Francisco will also be considered. Visa sponsorship is not available for this position.