Fullstack / AI Developer

Hi, I'm Andrzej.
I build systems that combine solid engineering with practical AI.

15+ years of commercial experience building and maintaining production web systems. For the past years I've specialized in applied AI: LLM agents, real-time voice AI, RAG, and NLP with personal-data anonymization.

📍 Opole, Poland / remote
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Andrzej Olczak

Selected achievements

Production AI microservices

Sole author of AI services running in production: job-title classification to occupation codes (Azure OpenAI, vector search, RAG) and a complete CV parsing & PII-anonymization pipeline (Presidio, NER - spaCy/Stanza, OCR).

Real-time AI voice agents

Evolved a recruitment voicebot from a scripted IVR to natural speech-to-speech conversations on the OpenAI Realtime API and ElevenLabs Conversational AI (Twilio Media Streams, barge-in handling).

Development & maintenance of a large ATS

~2,600 PHP files, custom MVC framework, ~100 job-board integrations, SOLR search. Recovered and optimized its MySQL performance three times under production load.

Production prompt engineering

Multilingual voice agent (11 languages) on Gemini 2.5/3.5 Flash: versioned prompts, anti-prompt-injection and GDPR guardrails, automated deployment pipeline.

LLM-based candidate scoring

Candidate-to-offer matching engine (Assistants API + Vector Stores) with statistical quality validation against recruiter judgments (Spearman correlation).

Research background

PhD studies in automation & robotics (time series, RNN/LSTM, sensor fusion) and 15+ publications, incl. Scientific Reports and Oncotarget.

Work experience

2022 – present
Weegree
Key Full Stack Officer → AI Developer
Development and maintenance of the es-candidate.com ATS and an internal ERP; own AI/NLP microservices (occupation-code classification, CV parsing & anonymization, scoring); AI voice agents; .NET 6/8 backend; React/TypeScript frontend; Flutter mobile app; collaboration on an NCBiR R&D project.
2021 – 2022
Martyna Kostka - Lectus Health & Beauty
PHP / JS / SQL Developer
Development and maintenance of the lectus24.pl online shop.
2020 – 2021
High School No. 1 in Opole
JS / PHP / SQL Developer
GPS location-based educational PWA game "Zagraj w BIO z LO": a walk around Bolko Island with map checkpoints unlocking content about local fauna and flora, a self-hosted map tile server and 8 interactive mini-games (BabylonJS 3D, PixiJS 2D). Plus a programming course for children.
2019 – 2021
ZAGA S.C.
JS / PHP / SQL Developer
Web applications and services for internal company needs.
2015 – 2019
Opole University of Technology
Teaching programming classes
Taught programming classes to university students throughout my doctoral studies, alongside research work and publications.
2013 – 2019
ARFixer Sp. z o.o.
Software Engineer
CMS and back-end architecture for mobile AR applications; production system for a wall-decoration manufacturer.
2011 – 2013
Quan Sp. z o.o.
Developer / administrator
Distributed systems for patient-traffic management in clinics.

Skills

AI Engineering

LLM agents RAG Tool / function calling MCP Structured output Embeddings & vector search Prompt engineering LLM evaluation Fine-tuning Neural networks (RNN/LSTM)

LLM Platforms

OpenAI API Azure OpenAI Google Gemini Anthropic Claude OpenRouter Ollama (local) LangChain

Voice AI

ElevenLabs OpenAI Realtime Twilio TTS / STT

NLP & Data

Presidio spaCy Stanza NER OCR PII / GDPR

Backend

Python FastAPI Django Flask C# / .NET 6-8 ASP.NET Core PHP

Frontend & Mobile

React TypeScript Redux JavaScript Flutter / Dart PWA

Databases

MySQL MS SQL / T-SQL PostgreSQL SQLite Apache SOLR Chroma

DevOps

Docker Kubernetes Git / SVN

🌱 Currently exploring: Brave Search API - web-search tooling for LLM agents.

Research & publications

PhD studies in automation & robotics (Opole University of Technology, 2015–2019; programme discontinued): time-series modeling with recurrent neural networks (RNN/LSTM), sensor fusion and adaptive filtering for mobile-device motion tracking (MEMS sensors). Author/co-author of 15+ scientific and conference publications, incl.:

Full publication list → ORCID

Conference talks (speaker)

Funded research task

No. DS-SD/72/WE/17, Opole University of Technology - "Positioning of mobile devices using adaptive-filtering tools and identification methods based on MEMS sensors."

Training & certifications

Education

2003 – 2008
M.Sc., Computer Science
Opole University of Technology
2006 – 2010
B.Eng., Management & Production Engineering
Opole University of Technology
2015 – 2019
PhD studies, Automation & Robotics
Opole University of Technology (discontinued)

Languages

Polishnative
Englishprofessional working proficiency
Germanbasic

Contact

Looking for an experienced Fullstack / AI developer? I'd be happy to talk.

E-mail kontakt@andrzejolczak.pl
Tel. +48 505 783 269
LinkedIn linkedin.com/in/andrzejolczak
ORCID 0000-0002-6834-3830

Curriculum Vitae

Download CV (PL) Download CV (EN)