Senior AI-first Engineer

We are looking for a Senior AI-first Engineer who combines deep technical expertise with a genuine, hands-on approach to AI-assisted development. You will work across varied client engagements — from modernizing legacy systems to architecting new products — and are expected to contribute at a high level regardless of project context. The ideal candidate has built a real, personalized AI development workflow — including custom skills, reusable prompt templates, and project-level instructions — and continues to refine it. Out-of-the-box tool usage is not sufficient for this role. This is a hybrid role, which means we'd like you to work in the office occasionally, especially during client visits or other important company meetings. Responsibilities • Design, develop, and maintain full-stack features with high standards of quality, performance, and reliability • Apply AI tools throughout the workflow: generation, refactoring, review, testing, and research • Contribute to architectural decisions — technology selection, system design, and trade-off analysis • Conduct thorough code reviews and uphold engineering best practices across the team • Identify risks, bottlenecks, and security concerns proactively and propose solutions • Work directly with clients in English — requirements clarification, technical discussions, progress updates • Mentor junior and mid-level engineers through day-to-day guidance and knowledge sharing • Stay current with AI tooling developments and contribute findings to the broader team Requirements • Hands-on experience with Claude Code, GitHub Copilot, Cursor, or equivalent AI coding assistants • Ability to create custom skills and sub-agents and orchestrate multiple AI agents in parallel for concurrent task execution • Strong prompt engineering skills; able to produce reliable, high-quality output and critically evaluate AI-generated results • Production-grade .NET / C# (REST APIs, middleware, dependency injection) with solid understanding of OAuth 2.0, OpenID Connect, and JWT • Deep proficiency in JavaScript and TypeScript • 2+ years of hands-on production experience with React • Strong grasp of state management, asynchronous patterns, and frontend testing • Confident designing systems across monoliths, microservices, and distributed architectures • Working knowledge of DDD, CQRS, Event Sourcing, and event-driven systems, including message brokers (Kafka, RabbitMQ, Azure Service Bus, or similar) • Hands-on use of Docker and working knowledge of Kubernetes, along with CI/CD pipelines (GitHub Actions, Azure DevOps, or similar) • Experience with cloud platforms (Azure, AWS, or GCP) and observability practices (structured logging, distributed tracing, alerting) • Solid background with SQL databases and ORMs; familiarity with NoSQL is a plus • Additional exposure to Python, Java, or Node.js is highly desirable • Clear communication skills in English (B2+), both written and spoken; comfortable in client-facing environments Salary ranges B2B 130 - 160 PLN/hour EC 17000 - 21000 PLN/month