Sr. Software Engineer, Kernels/CUDA (C++)

SpaceXSI • Palo Alto, CA

1d • $200,000 - $375,000

About The Position

SpaceXSI is building a large-scale AI supercomputer and the platform layer that runs on it. As part of the Compute Infrastructure team, the Sr. Software Engineer will work across low-level GPU kernel optimization, Linux kernel internals, orchestration, and virtualization to make training and inference faster, more reliable, and more scalable. The role’s work will directly contribute to Grok training performance and AI progress.

Requirements

• At least 5 years of experience with low-level system programming in C/C++.

Nice To Haves

• Deep low-level systems programming experience in C/C++/PTX/SASS.
• Strong experience with large-scale GPU clusters or distributed compute infrastructure at production scale.
• Hands-on experience with GPU kernel optimization using CUTLASS, custom kernels, and Nsight profiling.
• Track record of building or operating high-performance infrastructure for AI training or inference workloads.
• Ability to reason from first principles and optimize for memory-bound and compute-bound scenarios.

Responsibilities

• Design, build, and optimize massive GPU clusters for extreme-scale training and inference workloads.
• Develop and tune low-level CUDA kernels, including GeMM and Attention, using CUTLASS, Tensor Cores, and Nsight for performance.
• Profile, debug, and eliminate bottlenecks across GPU memory hierarchy, networking fabric, filesystems, and multi-GPU operation.
• Collaborate with AI research teams to deliver production-grade performance and scalability.

Benefits

• Equity
• Comprehensive medical coverage
• Vision coverage
• Dental coverage
• Access to a 401(k) retirement plan
• Short- and long-term disability insurance
• Life insurance
• Various other discounts and perks

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed