Senior Machine Learning / LLM Systems Engineer (f/m/x)

Sii Poland; Warszawa; On-site; PLN 150,000 - 200,000; Full time

Benefits offered by this job

Great Place to Work

Solid financial situation

Contracts with the biggest brands

Centre of internal trainings

Many experts you can learn from

Open and accessible management team

Profit sharing

Passion Sponsorship program

Regular integration events and trips

Comfortable and well-equipped offices

MySii app

Medical care

Job summary

Sii Poland is seeking a Senior Machine Learning / LLM Systems Engineer to deliver enterprise-class AI platforms. In this role, you will collaborate with teams to scale and optimize large-scale ML and LLM systems while managing performance across various initiatives.

The ideal candidate has extensive experience with ML workloads, strong C++ or CUDA optimization skills, and excellent Python proficiency. Join us for a great work environment and comprehensive benefits.

Qualifications

• Minimum 5 years of experience with LLM models and Machine Learning workloads.
• Strong experience with machine learning in production environments.
• Hands‑on work with large-scale distributed ML systems.

Responsibilities

• Scale ML and LLM models across multi-node, multi-accelerator clusters.
• Optimize latency, throughput, and resource efficiency of ML workloads.
• Design and operate distributed training and inference systems.
• Benchmark and profile AI workloads on real hardware platforms.
• Identify and resolve system-level performance bottlenecks.

Skills

LLM models and Machine Learning workloads

Production environments

Distributed ML systems

C++, CUDA optimization

Analyzing ML system performance

Python skills

English proficiency

Job description

Join Sii and play a key role in delivering enterprise-class AI platforms to international clients. As a Senior Machine Learning / LLM Systems Engineer, you will be responsible for scaling and optimizing large-scale ML and LLM systems. You will collaborate with cross-functional teams and support strategic AI and infrastructure initiatives across the organization.

Your tasks

• Scaling ML and LLM models across multi-node, multi-accelerator clusters
• Optimizing latency, throughput, and resource efficiency of ML workloads
• Designing and operating distributed training and inference systems
• Benchmarking and profiling AI workloads on real hardware platforms
• Identifying and resolving system-level performance bottlenecks

Requirements

• Minimum 5 years of experience with LLM models and Machine Learning workloads
• Strong experience with machine learning in production environments
• Hands‑on work with large-scale distributed ML systems
• Low‑level optimization skills in C++, CUDA, or similar technologies
• Proven ability to analyze and improve ML system performance
• Solid Python skills with an understanding of system-level performance
• Very good English skills, both spoken and written

Job no. JOB-CL97H

Sii ensures that all hiring decisions are made solely on the basis of qualifications and competence. We are committed to equal and fair treatment of all, regardless of legally protected characteristics. At Sii, we promote a diverse and inclusive work environment, in full compliance with applicable anti-discrimination laws.

Benefits For You

• Great Place to Work
• Solid financial situation
• Contracts with the biggest brands
• Centre of internal trainings
• Many experts you can learn from
• Open and accessible management team
• Profit sharing
• Passion Sponsorship program
• Regular integration events and trips
• Comfortable and well-equipped offices
• MySii app
• Medical care