AI Engineer (LLM) - Mid / Senior / Staff

Location: Poland

Contract: B2B or contract of employment

We’re building an intelligent AI shopping assistant in partnership with one of the fastest-growing companies in Poland (InPost) - a system that truly understands natural language and conversational context. We’re early in the journey, which means real influence on architecture, models, and the final shape of the product.

How this role works:

You will start by building the system as part of our team, working in a focused, greenfield setup. After a few months of introduction to the project, you will seamlessly continue working on the same product directly with the client, becoming part of the InPosts team responsible for its long-term development and scaling. There is no handover phase and no context switching - you stay with the same codebase, product, and technical challenges, while gaining long-term ownership and impact.

What you’ll work on:

• Designing, implementing, and deploying end-to-end NLP and deep learning systems

• Building LLM-powered applications that interact with real users

• Developing and maintaining production Python services

• Exposing models and pipelines via REST APIs (FastAPI, Flask)

• Working on retrieval models and techniques (RAG, embeddings, ranking)

• Evaluating, monitoring, and continuously improving model and system quality

• Scaling systems to handle enormous volumes of requests
  

Biggest challenges in this role:

• Greenfield project built from scratch

• High-scale, user-facing systems with strict performance and reliability requirements

• Designing systems meant for long-term ownership, not short-term delivery

• Balancing model quality, latency, and cost in production LLM systems

What you’ll learn:

• How to build LLM-powered products from scratch and take them to production

• Proven approaches to running LLMs in production at scale

• How to design, evaluate, and evolve NLP systems used by real users

• Best practices for production ML and AI system architecture
  

What you’ll get to try and experiment with:

• End-to-end ownership of LLM-based systems

• Optimizing retrieval models, RAG pipelines, and inference workflows

• Experimenting with different LLMs, prompting strategies, and system designs

• Solving performance and reliability challenges under heavy traffic

We want to offer you:

• Work with an experienced team that continually shares knowledge and is not afraid of testing new solutions

• Remote-first work with flexible hours

• Possibility to use one of our 2 offices in Poland (Warsaw or Szczecin), or book a Regus coworking space in your city

• Individual work tools – Macbook Pro, Dell screen, JBL headphones? You can tailor the equipment to your needs

• Sport & wellness benefit (Kafeteria MyBenefit)

• Private medical care

• A comprehensive benefits package after transitioning to our partner, including employee benefits, training opportunities, and occasional bonuses

Core requirements (all levels):

• Proven experience designing and deploying end-to-end NLP and deep learning solutions in production environments

• Hands-on experience building LLM-powered production systems (e.g. GPT, Claude, Gemini), including prompt engineering, evaluation, fine-tuning, and user-facing integrations

• Python proficiency with experience building and maintaining reliable production services and data pipelines

• Strong software engineering mindset, including code quality, testing, scalability, and production deployments

• Experience building RESTful APIs (FastAPI, Flask) to expose ML/LLM capabilities

• Curiosity and commitment to continuous learning in the NLP/LLM/AI space

• Collaborative team-player with strong communication skills

You will earn extra points for experience with:

• PyTorch, Hugging Face, and modern ML tooling for training and inference

• MLOps practices and tooling

• RAG systems, vector databases, and retrieval optimization

• multiple LLM providers or open-source models

• high-traffic, high-availability systems

Seniority levels:

Mid AI Engineer:

• At least 1 year of experience working with NLP / LLM systems in production

• Experience contributing to production ML or AI services

• Eagerness to learn and grow in a fast-moving environment

Senior AI Engineer:

• At least 4 years of experience in ML / AI engineering

• Proven experience owning production NLP or LLM systems

• Strong understanding of scalability, performance, and system design

Staff AI Engineer:

• At least 6 years of experience in ML / AI engineering

• Experience designing large-scale, production LLM architectures

• Ability to drive technical direction and mentor other engineers