Senior AI System Engineer

Summary

Join Callstack as a Senior AI System Engineer and work with top Silicon Valley and Fortune 500 companies. Act as a trusted AI architect and consultant, designing and owning end-to-end LLM & multi-agent architectures. Create and publish libraries utilizing local on-device models and design papers. Build cloud-native AI infrastructure and implement AI governance & monitoring. Evaluate, benchmark, and create custom models. Contribute to the open-source community and mentor other engineers. This role requires a seasoned AI/ML engineer with 10+ years of experience and a Bachelor's, Master's, or Ph.D. in a related field. Fluency in Python and TypeScript, along with skills in vector search & RAG pipelines, is essential. The ideal candidate is data-driven, open-source minded, and a good communicator.

Requirements

• A seasoned AI/ML engineer with proven track record designing and shipping production AI systems (LLMs, NLP, computer vision, or multi-modal)
• Have 10+ years of experience in Software Engineering
• Bachelor's Degree, Master's Degree or Ph. D in Computer Science, Data Science, Artificial Intelligence, or a related field
• Fluent in Python and comfortable with TypeScript
• Skilled at vector search & RAG pipelines and understand embedding selection, chunking, and retrieval tuning
• Comfortable designing multi-agent orchestration
• Understand AI governance, security, and MLOps
• Data-driven - you benchmark, profile, and optimize everything from prompt tokens to GPU utilization
• Good communicator in English (B2+), able to explain complex concepts to technical and non-technical stakeholders
• Proactive, self-driven, and a team player who loves sharing knowledge and elevating those around you

Responsibilities

• Act as a trusted AI architect & consultant for our enterprise clients, helping them turn ambitious ideas into robust, production-ready solutions across cloud, edge, and on-prem environments
• Design and own end-to-end LLM & multi-agent architectures - from vector-based RAG pipelines and document-processing workflows to multi-agent orchestration and autonomous decision frameworks
• Create and publish libraries utilizing local on-device models
• Create and publish design papers on behalf of the company together with our Ph. D team
• Build cloud-native AI infrastructure on AWS or equivalent on Cloudflare / GCP with security, governance, and cost optimization baked in
• Define and implement AI governance & monitoring (bias detection, drift tracking, compliance reporting) to keep models accurate, explainable, and audit-ready
• Evaluate, benchmark, and create custom models - open-source and commercial
• Contribute to the open-source community through internal R&D initiatives
• Stay one step ahead by experimenting with the “next big thing” in AI
• Mentor and inspire engineers around you, sharing knowledge through tech talks, code reviews, and architectural workshops

Preferred Qualifications

• Open-source minded - public GitHub contributions, conference talks, or community forum activity are huge pluses
• Fun to work with :)

Benefits

• 24 paid days off & 30 days paid sick leave for B2B contractors
• Fully-covered life insurance
• Private healthcare for you and your family
• Free access to mental health platform - Helping Hand
• Multisport Card or monthly allowance for other sports activities
• Individual Wellbeing & Development Budget
• Monthly lunch allowance
• Accounting costs refund for B2B contractors
• Flexible working hours and fully remote work possibility
• Cool office in Wrocław city center
• Magnificent team events and activities
• Company-wide workation and team building workshops
• Top-notch hardware - Apple devices
• Possibility to participate in React Universe Conf