Runtime Engineer

What MatX Is Building

MatX is building custom silicon for large-language-model inference and training, with HW/SW co-design across ISA, RTL, simulator, compiler, and kernels so each layer benefits from the others. The runtime owns the host-side stack and the contracts that bind those teams together.

• Build the host-side interface library — device memory management, DMA, streams and events, sync primitives — that every compiler‑emitted program runs on top of
• Own and extend the executable format: the compiler→runtime contract, its versioning, the weight and quantization layouts that let compiler and runtime evolve independently
• Design the custom‑kernel ABI — calling convention, sync semantics, lifecycle — and the host‑side marshaling layer (DLPack, the buffer protocol, numpy) that gets Python tensors to the device
• Build Python bindings via PyO3, with a C‑ABI shim as the alternative integration path for downstream consumers
• Build the LLM inference serving stack — paged KV cache, continuous batching, request scheduling, token streaming — and the cluster orchestration primitives underneath it
• Bring up interconnect topology from the host and own the failure‑detection and clean‑teardown path for stop‑restructure‑resume recovery across racks
• Design what the chip exposes to host‑side profilers and debuggers — perf counters, traces, and the Python surfaces ML engineers actually use — and hit measurable performance targets on runtime overhead and serving throughput

• Strong experience in a systems programming language — Rust, C, C++, or Go — including memory management, allocator design, and FFI/ABI work
• Have built Python interop layers in production (PyO3, ctypes, pybind
  11, or equivalent C‑ABI bridging)
• Have designed and maintained API or ABI contracts between teams — versioning, evolution, breaking‑change discipline — not just consumed someone else’s
• Hands‑on with at least one accelerator programming model (CUDA, ROCm, oneAPI Level Zero, TPU, or comparable) — enough to reason about device memory, async execution, and kernel launch
• ML‑systems literate — comfortable with the training and inference loop, what collectives do, what a tensor layout is. Research depth not required.

• LLM inference internals — vLLM, TensorRT‑LLM, or SGLang (paged attention, scheduler design)
• Rust at depth, including proc macros, unsafe with soundness reasoning, and complex lifetime/trait work
• Custom allocator design (slab, paged, arena) or other low‑level memory work
• ML framework integration experience (PyTorch custom backends, JAX/XLA, ONNX runtime)
• Profiler or tracing infrastructure work (perfetto, Nsight, or a custom stack)
• Driver‑adjacent or kernel‑by‑pass work, or prior new‑silicon bring‑up

The US base salary for this full‑time position is determined based on a variety of factors including role, experience, location, job‑related skills, and relevant education and training. Career length is only a guideline for compensation.

• Early Career - $160,000 - $250,000 + equity
• Mid Career - $175,000 - $362,500 + equity
• Senior Career - $250,000 - $475,000 + equity

• Time off: 4 weeks PTO (accrued) + 12 company Holidays + up to 3 weeks remote work
• Health:
  Company‑subsidized Medical (Kaiser or Anthem) for employees & dependents, Guardian Dental and Vision insurances for employee & dependents, and life insurance (employee only), plus HSA and FSA offerings via Lively. See attached benefits 1‑pager and full benefits guide for more info on benefits.
• Financial Wellbeing:
  Choose from Roth IRA/ 401K (or both) retirement plans with up to 5% company contribution to 401K (even if you don't contribute). Also, 100% company‑paid life insurance (up to $300K) and long‑term disability insurances.
• Professional Development: $1500 Professional Development Budget (per year)
• Team Meals:
  MatX provides onsite team lunch & dinner Monday - Friday, with your choice of ordering via WeBox, Specialty’s or via our reimbursement system
• Commute on Us:
  Commute on our company Uber account, or reimburse your train rides. Either way, we pay 100% for your daily commute.
• MatX E[x]tras: $50/mo to use on the perk you value most
• C…