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Thinking Machines Lab

Research Engineer, Infrastructure, Kernels

Thinking Machines Lab is hiring a Research Engineer, Infrastructure, Kernels in San Francisco, United States. It pays $400k-$500k a year and Level rates it ; you can apply on Thinking Machines Lab.

Level's read on this job

  • Builds AI ●●●● is how Level rates this role: the job is building AI systems.
  • The posting mentions visa sponsorship.
  • The posting mentions PyTorch and JAX among its tools and skills.
  • Thinking Machines Lab has 57 other open roles on Level.

AI in this role

PyTorchJAX
About Thinking Machines

The mission of Thinking Machines is to build AI that extends human will and judgment. We are training frontier models with Inkling, developing Tinker to let people make models their own, and crafting interfaces that broaden human-AI communication. We believe the future worth building is human, and we're hiring people who want to build it.

About the Role

We’re looking for an infrastructure research engineer to design, optimize, and maintain the compute foundations that power large-scale language model training. You will develop high-performance ML kernels (e.g., CUDA, CuTe, Triton), enable efficient low-precision arithmetic, and improve the distributed compute stack that makes training large models possible.

This role is perfect for an engineer who enjoys working close to the metal and across the research boundary. You’ll collaborate with researchers and systems architects to bridge algorithmic design with hardware efficiency. You’ll prototype new kernel implementations, profile performance across hardware generations, and help define the numerical and parallelism strategies that determine how we scale next-generation AI systems.

Note: This is an "evergreen role" that we keep open on an on-going basis to express interest. We receive many applications, and there may not always be an immediate role that aligns perfectly with your experience and skills. Still, we encourage you to apply. We continuously review applications and reach out to applicants as new opportunities open. You are welcome to reapply if you get more experience, but please avoid applying more than once every 6 months. You may also find that we put up postings for singular roles for separate, project or team specific needs. In those cases, you're welcome to apply directly in addition to an evergreen role.

What You’ll Do

  • Design and implement custom ML kernels (e.g., CUDA, CuTe, Triton) for core LLM operations such as attention, matrix multiplication, gating, and normalization, optimized for modern GPU and accelerator architectures.

  • Design and think through compute primitives to reduce memory bandwidth bottlenecks and improve kernel compute efficiency.

  • Collaborate with research teams to align kernel-level optimizations with model architecture and algorithmic goals.

  • Develop and maintain a library of reusable kernels and performance benchmarks that serve as the foundation for internal model training.

  • Contribute to infrastructure stability and scalability, ensuring reproducibility, consistency across precision formats, and high utilization of compute resources.

  • Document and share insights through internal talks, technical papers, or open-source contributions to strengthen the broader ML systems community.

Skills and Qualifications

Minimum qualifications:

  • Bachelor’s degree or equivalent experience in computer science, electrical engineering, statistics, machine learning, physics, robotics, or similar.

  • Strong engineering skills, ability to contribute performant, maintainable code and debug in complex codebases

  • Understanding of deep learning frameworks (e.g., PyTorch, JAX) and their underlying system architectures.

  • Thrive in a highly collaborative environment involving many, different cross-functional partners and subject matter experts.

  • A bias for action with a mindset to take initiative to work across different stacks and different teams where you spot the opportunity to make sure something ships.

  • Proficiency in CUDA, CuTe, Triton, or other GPU programming frameworks.

  • Demonstrated ability to analyze, profile, and optimize compute-intensive workloads.

Preferred qualifications — we encourage you to apply if you meet some but not all of these:

  • Experience training or supporting large-scale language models with tens of billions of parameters or more.

  • Track record of improving research productivity through infrastructure design or process improvements.

  • Experience developing or tuning kernels for deep learning frameworks such as PyTorch, JAX, or custom accelerators.

  • Familiarity with tensor parallelism, pipeline parallelism, or distributed data processing frameworks.

  • Experience implementing low-precision formats (FP8, INT8, block floating point) or contributing to related compiler stacks (e.g., XLA, TVM).

  • Contributions to open-source GPU, ML systems, or compiler optimization projects.

  • Prior research or engineering experience in numerical optimization, communication-efficient training, or scalable AI infrastructure.

Logistics

  • Location: This role is based in San Francisco, California.

  • Compensation: Depending on background, skills and experience, the expected annual salary range for this position is $400,000 - $500,000 USD.

  • Visa sponsorship: We sponsor visas. While we can't guarantee success for every candidate or role, if you're the right fit, we're committed to working through the visa process together.

  • Benefits: Thinking Machines offers generous health, dental, and vision benefits, unlimited PTO, paid parental leave, and relocation support as needed.

How we rate this

Research Engineer, Infrastructure, Kernels at Thinking Machines Lab rates 99 out of 100 for how much of the daily work is AI. That makes it Builds AI (AI Level 4 of 4). The level is about AI in the job, not seniority.

Classification

Builds AI. The job is building AI systems.

  1. ●●●● Builds AI80 to 100
  2. ●●●○ Works on AI60 to 79
  3. ●●○○ Uses AI40 to 59
  4. ●○○○ Little AI0 to 39

Levels come from how often the tools, models and workflows of the role are named in the posting itself. Read the description and count the AI tools, models and workflows it names.

Prepare for this job

Built from this posting and from similar jobs on Level.

Skills and AI tools this role asks for

PyTorchJAX

Questions you could be asked

  1. What's a project where you used PyTorch hands-on?
  2. Walk me through how you've used JAX in your day-to-day work.
  3. How would you decide a model or AI system is ready to ship?
  4. Tell me about a time a model underperformed in production. How did you find out, and what did you change?

Adapt your resume

  • List these exact terms on your resume: PyTorch and JAX. An applicant tracking system matches the wording, not the idea.
  • Attach one line of real, concrete experience to at least one of them. A tool named with nothing behind it rarely survives a human read.
  • Lead with what you built, trained or shipped. This role is judged on the AI system itself, not the tools around it.

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