River AI Verified

AI Infrastructure, Model Serving

Software Engineer, GPU Kernels

Name: RiseMe
Availability: InStock

Palo Alto, CAOnsiteFull Time$200,000–$420,000 /yrPosted 1 month ago

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Required skills

GPU kernels
compute primitives
performance-critical operations
attention
matrix multiplication
mixture-of-experts execution
low-precision computation
memory access
tiling
synchronization

Nice to have

NVIDIA Blackwell
NVIDIA Hopper
grouped GEMMs
low-rank adapters
quantized weight layouts
Triton

Role summary

River AI is seeking exceptional GPU kernel engineers to develop the core compute primitives for their personal AI infrastructure. This role involves optimizing performance-critical operations like attention, matrix multiplication, and low-precision computations for training and inference. You will work closely with researchers and systems engineers to identify bottlenecks, implement and validate kernels, and integrate improvements into production runtimes. The ideal candidate has a strong background in GPU architecture, parallel programming, and numerical computing, with experience in CUDA, C++, and Python.

At River AI, our mission is to create personal AI owned and shaped by each individual. To achieve this, we are rewriting the entire stack from scratch: personal hardware for local inference, bespoke training infrastructure, next-generation UIs, and frontier deep learning research.

Who we are

We are scientists, engineers, and builders from the industry's top tech companies and AI labs. We bring a proven track record of scaling consumer systems for hundreds of millions of users and architecting the pre-training infrastructure behind today's frontier models.

About the Role

We are looking for exceptional GPU kernel engineers to build the compute primitives behind River’s training and inference infrastructure. Your goal is to make large models faster to train and more efficient to serve.

You will own performance-critical operations, including attention, matrix multiplication, mixture-of-experts execution, and low-precision computation. Working closely with researchers and systems engineers, you will identify bottlenecks, implement kernels, validate correctness, and bring improvements into production.

What You’ll Do

Build fast GPU kernels for attention, matrix multiplication, expert routing, and related operations.

Optimize memory access, tiling, and synchronization to make efficient use of GPU hardware.

Develop FP8, FP4, and mixed-precision kernels while preserving numerical correctness.

Accelerate fine-tuning and RL through optimized adapters, backward passes, and fused operations.

Profile real workloads and integrate improvements into training and inference runtimes.

Build reproducible benchmarks that verify correctness, gradients, and performance.

Skills & Qualifications

Minimum Qualifications:

Bachelor’s degree in Computer Science, Computer Engineering, or equivalent practical experience.

Experience optimizing GPU kernels with CUDA, Triton, CUTLASS, CuTe, or comparable tools.

Strong understanding of GPU architecture, memory hierarchies, and parallel execution.

Proficiency in C++ and Python.

Strong foundations in linear algebra, floating-point arithmetic, and numerical computing.

Strong debugging and profiling skills, with a collaborative approach to engineering.

Preferred Qualifications: (We encourage you to apply even if you don't meet all of these)

Experience optimizing for NVIDIA Blackwell or Hopper GPUs.

Work on attention, mixture-of-experts kernels, grouped GEMMs, or low-rank adapters.

Experience implementing backward passes and validating gradients.

Familiarity with FP8, FP4, and quantized weight layouts.

Experience integrating custom operators into PyTorch, SGLang, vLLM, or similar frameworks.

Open-source contributions or a track record of shipping substantial kernel optimizations.

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.

Ready to apply?

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