Software Engineer, River API

About the Role

We are looking for exceptional systems engineers to build the high-performance engines that train our models. Your goal is to make training at River fast, reliable, and massively scalable.

You will take ownership of our core infrastructure stack; from writing custom GPU kernels to managing clusters of thousands of nodes, ensuring our researchers can focus on science rather than system bottlenecks.

What You’ll Do

• Architect and deploy fault-tolerant distributed systems for training and inference workloads across clusters with thousands of nodes.
• Design high-performance kernels to maximize tensor operation efficiency, memory throughput, and networking over InfiniBand/RDMA.
• Profile systems end-to-end to resolve blockers across hardware, software, data loading pipelines, and collective communication primitives.
• Partner directly with research scientists to rapidly implement, optimize, and scale experimental model architectures.

Skills & Qualifications

Minimum Qualifications:

• Bachelor’s degree in Computer Science, Computer Engineering, or equivalent practical industry experience.
• Deep expertise in systems-level languages (C, C++, or Rust) with a track record of writing performant, maintainable code.
• Strong foundation in computer architecture, memory management, and concurrent programming.
• Exceptional debugging skills, especially when tackling complex, non-deterministic issues in distributed environments.
• A highly collaborative mindset and a bias for action to push boundaries across the stack.

• Hands-on experience with modern AI frameworks (e.g., PyTorch, JAX) and tooling for large-scale model training.
• Deep familiarity with modern GPU architectures (NVIDIA/AMD) and hardware constraints (HBM bandwidth, PCIe limits).
• A proven track record of shipping and maintaining high-performance distributed systems or low-level software libraries.

Logistics & Benefits

• Location: Palo Alto, California.
• Compensation: Depending on experience and skills the expected base pay is $200,000 - $420,000 USD per year, plus equity.
• Benefits: Comprehensive health, dental, and vision insurance; unlimited PTO; and relocation assistance as needed.
• Visa Sponsorship: We sponsor visas and are committed to supporting the process for the right candidate.