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?
Yo
u 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
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Questions:
- Full name
- Email address
- Resume/CV
- Phone
- How did you hear about this job offer?
- Callstack website
- Conferences and Meetups
- Just Join IT
- Other job board
- Linkedin
- X post
- Other
- Do you currently have a valid authorization to work in Poland or in the European Union (without the need for visa sponsorship)?
- Yes
- No
- I will require sponsorship
- What form of collaboration do you prefer?
- B2B
- Contract of employment
- Contract of mandate
- What is your current notice period?
- What are your monthly salary expectations? (net on B2B or gross on employment contract/contract of mandate)
- Could you please provide us with your portfolio (e.g. github)?
-
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