Senior AI System Engineer

Callstack was founded in 2016 by Mike Grabowski and Anna 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!

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 in Open 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, or React 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!

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

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 :)

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

What we offer:
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