Wrocław, Lower Silesian Voivodeship, Poland · Remote OK
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 …
Skills: AI Architecture, LLM, Multi-agent Orchestration, RAG Pipelines, Python
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Design and implement end-to-end LLM and multi-agent architectures for enterprise clients across cloud and edge environments. Lead AI governance, monitoring, and R&D initiatives while mentoring other engineers.
Requires 7+ years of software engineering experience and a degree in Computer Science or a related AI field. Must be proficient in Python, TypeScript, and RAG pipelines with a strong track record of shipping production AI systems.
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
Shipping products at AI speed. Building tools for agents. 39M monthly downloads. React Foundation Founding Members.
Callstack is an AI-native engineering company. We build cross-platform products with agent-driven workflows, then help enterprise teams adopt the exact same way of working. Backed by 10+ years of React Native leadership, our work combines framework expertise with the tools and systems needed to ship at AI speed. We do that in four areas: • Engineering: We build complex React and React Native products with AI-native workflows, so teams can ship roadmap work faster, launch across platforms more efficiently, and solve hard engineering problems without trading away quality. • Infrastructure: We build the systems that let faster output become faster shipping, from agentic QA and device automation to CI/CD and observability, so delivery stays reliable as AI speed increases. • Adoption: We turn AI tools into a repeatable way of working by configuring the stack, training engineers, and measuring impact, so teams get more than experimentation and leadership gets a clearer return on AI investment. • Governance: We keep enterprise AI under control at scale with private models, tooling audits, tighter access, and smarter model routing, so teams can move faster without creating security, compliance, or cost problems. We also build specialized tooling for this new era, including Apex, our specialized model for React Native that cuts frontier-model costs, and Agent Device, which gives AI agents control over real iOS and Android apps. And we bring the community into that conversation through Agent Conf, where the future of agent-driven development gets shaped in public. This work builds on more than a decade of React Native leadership: • Core Contributors to React Native and Founding Members of the React Foundation. • 10+ years in the space and 100+ enterprise projects delivered. • Open-source software behind more than 30M monthly downloads. Learn more at callstack.com.
Offices: ulica Prosta 36, Wrocław, Dolnośląskie 53-508, PL
Shipping products at AI speed. Building tools for agents. 39M monthly downloads. React Foundation Founding Members.
Callstack is an AI-native engineering company. We build cross-platform products with agent-driven workflows, then help enterprise teams adopt the exact same way of working. Backed by 10+ years of React Native leadership, our work combines framework expertise with the tools and systems needed to ship at AI speed. We do that in four areas: • Engineering: We build complex React and React Native products with AI-native workflows, so teams can ship roadmap work faster, launch across platforms more efficiently, and solve hard engineering problems without trading away quality. • Infrastructure: We build the systems that let faster output become faster shipping, from agentic QA and device automation to CI/CD and observability, so delivery stays reliable as AI speed increases. • Adoption: We turn AI tools into a repeatable way of working by configuring the stack, training engineers, and measuring impact, so teams get more than experimentation and leadership gets a clearer return on AI investment. • Governance: We keep enterprise AI under control at scale with private models, tooling audits, tighter access, and smarter model routing, so teams can move faster without creating security, compliance, or cost problems. We also build specialized tooling for this new era, including Apex, our specialized model for React Native that cuts frontier-model costs, and Agent Device, which gives AI agents control over real iOS and Android apps. And we bring the community into that conversation through Agent Conf, where the future of agent-driven development gets shaped in public. This work builds on more than a decade of React Native leadership: • Core Contributors to React Native and Founding Members of the React Foundation. • 10+ years in the space and 100+ enterprise projects delivered. • Open-source software behind more than 30M monthly downloads. Learn more at callstack.com.
Offices: ulica Prosta 36, Wrocław, Dolnośląskie 53-508, PL
