Senior AI System Engineer

Role Summary

Callstack was founded in 2016 byMike GrabowskiandAnna Lankauf . Our company provides top cross-platform consultancy &development in React.js and React Native. We co-create the technology and collaborate with the Meta team on shaping the technology as core contributors and innovators.

Our main goal is to drive and accelerate software development innovation. To achieve that, we follow our major rule:

We don’t follow best practices. We set them!

Responsibilities

As a Senior AI System Engineer you will

• 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 R&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

Requirements

You are the right candidate if you are

• A seasoned AI/ML engineer with proven track record designing and shipping production AI systems (LLMs, NLP, computer vision, or multi-modal)
• Have 7+ 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
• Open-source minded - public GitHub contributions, conference talks, or community forum activity are huge pluses
• Fluent communicator in English (min. 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
• 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

About the Company

What is unique about working at Callstack ?

You will work with the best React Native experts on applications used by millions worldwide.

You have a possibility to contribute to our projects inOpen Source like React Native Paper, Linaria, RN Testing Library etc.

There are plenty of possibilities to showcase your expertise: You can speak at our conference, be featured in our blog, orReact Universe On Air episode.

You are the one to decide in which area you want to grow, you’ll have an individual self-development budget to upgrade your soft skills, managing skills or become a Mentor in the future.

Join us and work with the TOP Silicon Valley and Fortune 500 companies in the USA!

Why work with us? Because you can

• Work on software used by millions
• Take part in our Open Source projects
• Grow in your unique expert role
• Code with the top experts and community leaders
• Showcase your expertise by speaking at our conference, being featured in our blog or podcast episode
• Co-create and shape core technology
• Join the React Native community
• Develop soft skills