About Voltspan
Voltspan helps companies keep their data in their own hands and turn it into models of their own. We build from the power up: our own GPU clusters in US data centers, the sandboxes and inference agents run on, and the training behind them. We are growing across every layer of the stack.
About the role
Make every GPU we run do more. You will profile and optimize training and inference down to the kernel level on NVIDIA's newest systems.
What you'll do
- Profile training and inference workloads and remove bottlenecks
- Write and tune kernels for attention, MoE and communication
- Tune NCCL, NVLink and InfiniBand performance at rack and cluster scale
- Bring up and benchmark new hardware generations
What we're looking for
- Experience writing CUDA, Triton or CUTLASS kernels
- Deep understanding of GPU architecture
- Comfort with profilers like Nsight
Nice to have
- Experience on Blackwell or Hopper at scale
- Collective communication tuning
Projects you might work on
- Reach top-tier MFU for RL training on a full GB300 NVL72 rack
- Benchmark Vera Rubin the week it arrives
Logistics
San Jose, CA · Hybrid · Full-time
If a role excites you but you don't meet every qualification, apply anyway. We care more about what you have built than about a checklist.
Salary range, visa sponsorship and benefits will be added before this posting goes live.
How we work
- Small teams, big systems. Everyone here owns real infrastructure and real customers from week one.
- From volts to agents. Work moves across the whole stack, so you will see how your piece connects to power, GPUs, tokens and agents.
- We run what we build. The people who write the software also operate it, next to the people who rack the hardware.
Equal opportunity
Voltspan is an equal opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, veteran status or any other characteristic protected by law. We consider qualified applicants with arrest and conviction records in accordance with the California Fair Chance Act.
If you need an accommodation during the application process, let us know.