LLM Inference Engineer

Majestic Labs ai; Los Altos (CA); On-site; USD 210,000 - 350,000; Full time

Job summary

Majestic Labs is seeking an experienced engineer to own the end-to-end LLM serving stack on Majestic hardware. You will port leading frameworks like vLLM and SGLang to our accelerator and optimize them for peak throughput, latency, and scale.

You will collaborate with kernel, compiler, and hardware teams to push performance and reliability in production deployments, shaping the future of high-performance AI inference.

Qualifications

• 5+ years building or operating production LLM inference and serving systems.
• Hands-on work with vLLM, SGLang, TensorRT-LLM, Fireworks or similar, including scheduler and KV cache.
• Strong Python and C++, with fluency between the two.
• Understanding of transformer inference, KV cache, batching and latency concepts.
• Distributed inference experience across multiple devices.

Responsibilities

• The serving stack end to end — bring up and adapt a modern inference framework to Majestic hardware.
• The runtime hot path — batching, scheduler, KV cache, and prefill/decode disaggregation.
• Distributed inference at scale — tensor and pipeline parallelism across accelerators connected to CCL.
• Multi-modal pipeline — image, audio, and video preprocessing and integration.
• Inference-time techniques — speculative decoding, prefix caching, structured decoding.
• End-to-end performance — profile, benchmark, and drive improvements with kernel and compiler teams.

Skills

Python

C++

LLM inference

Distributed systems

Performance optimization

Problem solving

Tools

vLLM

SGLang

TensorRT-LLM

Fireworks

CCL

Job description

We’re a fast-moving, US-Israeli AI startup building next-generation infrastructure for the world’s most demanding AI workloads. Our mission is to accelerate the future of intelligence and make it ubiquitously accessible by delivering full stack custom AI servers optimized for large-scale inference and training. Backed by top-tier investors and led by industry veterans, we’re scaling rapidly. We seek forward-thinking engineers and operators who thrive in a collaborative environment and excel at solving complex challenges from first principles. If you want to build infrastructure that fundamentally changes what the world can accomplish with AI, come join us!

About The Position

In this high-impact role, you are the bridge between cutting-edge custom silicon and production-grade AI. You will own the end-to-end LLM serving stack on Majestic hardware, architecting everything from serving APIs down to KV cache management, batching, and scheduling. Your primary mission is to port leading frameworks like vLLM and SGLang to our accelerator and optimize them for peak performance. Because our architecture offers memory headroom, you won't just match traditional GPUs; you will shatter their limits on throughput, batch sizes, and context lengths. As you hunt down bottlenecks, your insights will directly steer our future kernel, compiler, and hardware development.

Responsibilities

• The serving stack, end to end — bring up and adapt a modern inference framework (vLLM, SGLang, or similar) to run on Majestic hardware.
• The runtime hot path — continuous batching, the scheduler, paged KV cache, and prefill/decode disaggregation.
• Distributed inference at scale — tensor, pipeline, and expert parallelism across accelerators, wired into our collective communication library (CCL).
• The multi-modal pipeline — image, audio, and video preprocessing, encoder integration, and mixed-modality batching.
• Inference-time techniques — speculative decoding, prefix caching, and structured decoding.
• End-to-end performance — profile, benchmark, and hunt down bottlenecks across the full serving path, feeding findings back to the kernel, compiler, and hardware teams.

Requirements

• 5+ years building or operating production LLM inference and serving systems.
• Deep, hands‑on work with a modern inference framework vLLM, SGLang, TensorRT-LLM, Fireworks, or similar including its scheduler, paged attention / KV cache, model executor, and backend integration points.
• Strong Python and C++, with the ability to move fluidly between the two.
• A real grasp of transformer inference the prefill/decode split, KV cache behavior, and how batching dynamics shape latency and throughput.
• Distributed inference experience tensor and pipeline parallelism across multiple devices.
• An instinct for performance you can profile an end-to-end stack and chase a regression from the serving API all the way down to the kernel.

We seek smart, curious, self-driven individuals who enjoy creative problem-solving and continuous learning. Even if you don't meet all requirements, we'd love to hear from you if you have the mindset to tackle complex challenges.

Majestic Labs is an equal opportunity employer deeply committed to diversity of background and thought. If you are ready to dare greatly, learn from mistakes, engage in vigorous debates, and help create a step-function shift in human technical capability, we want to meet you!