Senior Full-Stack Software Engineer

Quick Facts

• Role: Senior Full-Stack Software Engineer (AI / LLM / RAG)

Description

Build and maintain web applications and backend services with an emphasis on LLM-based RAG systems. You will design fullstack solutions using React, Node.js, and Python, implement document-to-embedding and semantic retrieval pipelines, and deliver the right context to language models. You’ll also evaluate and improve search and generated answers, while making architecture choices and ensuring quality, security, performance, and scalability.

Responsibilities

• Design, develop, and maintain web applications and backend services
• Build fullstack solutions with React, Node.js, and Python
• Develop LLM applications, especially RAG systems
• Implement document processing, embeddings, information retrieval, and context delivery to models
• Analyze and improve retrieval quality and model-generated answers
• Make architectural decisions and select implementation approaches
• Ensure quality, testability, security, performance, and scalability
• Solve complex technical problems, including reliability and performance in distributed systems
• Collaborate with team members and international clients
• Experiment with new AI models and technologies to support development

Requirements

• Minimum 5 years of programming and software development experience
• Solid software engineering foundations; ability to independently design and evolve reliable applications
• Practical experience with LLMs and understanding of RAG architecture (commercial or personal projects)
• Understanding of embeddings, semantic search, vector databases, and methods for providing context to LLMs
• Knowledge of LLM limitations and ways to evaluate answer quality and improve results
• Backend experience; knowledge of Python or another language enabling effective work in a Python stack
• Knowledge of Node.js and React (or a related stack) to start quickly
• Ability to justify technical decisions, analyze trade-offs, and explain solutions
• Familiarity with best practices for coding, testing, architecture design, and performance problem-solving
• English level at least B2

Benefits

• Hybrid work model (2–3 days per week in an office in Warsaw)
• B2B contract
• Work in a technical and experienced team
• Real influence on architecture, technology choices, and the direction of AI solutions
• Projects in AI, automation, and cybersecurity
• Startup culture with high independence and minimal corporate bureaucracy