
51 - 200 employees
Founded 2016
💼 Consulting
📣 Marketing
Consulting • Marketing • Software Engineering
Callstack is a leading software engineering consultancy that specializes in app development and technological transformation using React and React Native. They provide end-to-end product development services including mobile and web app development, app performance optimization, and tech stack upgrades. Their expertise in the React ecosystem makes them a trusted partner for companies looking to enhance and innovate their software solutions. Callstack also focuses on educating and upskilling development teams, enabling organizations to stay competitive and efficient.
🕒 June 16
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51 - 200 employees
Founded 2016
💼 Consulting
📣 Marketing
Consulting • Marketing • Software Engineering
Callstack is a leading software engineering consultancy that specializes in app development and technological transformation using React and React Native. They provide end-to-end product development services including mobile and web app development, app performance optimization, and tech stack upgrades. Their expertise in the React ecosystem makes them a trusted partner for companies looking to enhance and innovate their software solutions. Callstack also focuses on educating and upskilling development teams, enabling organizations to stay competitive and efficient.
• 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
• 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 :)
• 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
Apply Now🕒 June 16
Python
VMware
🕒 May 5
Mid Linux & Cloud Systems Engineer maintaining IT infrastructure stability and security for clients like Castorama and Medicover. Collaborating with SysOps and DevOps experts in remote settings.
🗣️🇵🇱 Polish Required
Ansible
AWS
Azure
Cloud
Google Cloud Platform
Grafana
Linux
Prometheus
Puppet
TCP/IP
Terraform
🕒 March 31
System Engineer creating documentation and supporting automotive projects for Infotree Global Solutions. Involves collaboration, customer communication, and adherence to E&S quality standards.
🕒 February 25
Systems Engineer maintaining critical infrastructure for online systems and applications in e-commerce and fintech projects. Automating processes and ensuring reliability in server environments.
🗣️🇵🇱 Polish Required
Jest
Linux
Python
TCP/IP
🕒 January 25
Senior Systems Engineer supporting high-scale cloud infrastructure in financial services domain. Focus on AWS and GCP while ensuring security and performance of production-critical systems.
Ansible
AWS
Cloud
Docker
Google Cloud Platform
Kubernetes
Linux
Python
Terraform