Konstantinos Giantsios
Verified Expert in Engineering
Machine Learning Engineer and Developer
Thessaloniki, Greece
Toptal member since August 17, 2026
Across gaming and publishing technology, Konstantinos has spent five years building machine learning solutions for companies including Kaizen Gaming and Atypon Systems. His toolkit centers on Docker, FastAPI, and Apache Spark. While at Atypon Systems, Konstantinos boosted recommended article click-through rate by 100% and search click-through rate by 20%.
Portfolio
Experience
- Natural Language Processing (NLP) - 5 years
- Python - 5 years
- Apache Spark - 4 years
- Docker - 4 years
- PyTorch - 3 years
- LangGraph - 3 years
- Elasticsearch - 2 years
- Agentic AI - 2 years
Preferred Environment
Docker, FastAPI, Apache Spark, PySpark, Databricks, Microsoft Azure, Elasticsearch, OpenCV
The most amazing...
...hybrid retrieval system I've architected doubled the recommended article click-through rate and increased the search click-through rate by 20%.
Work Experience
Machine Learning Engineer
Kaizen Gaming
- Engineered robust data pipelines employing Apache Spark/PySpark and Databricks on Microsoft Azure, processing large-scale interaction data to power an agentic AI chatbot for customer experience analysis.
- Co-designed and implemented a multi-agent sports betting Copilot using Python, LangChain, and LangGraph, delivering an interactive assistant capable of complex reasoning and resolving nuanced user queries.
- Deployed complex agentic AI solutions as scalable RESTful API services utilizing FastAPI, Docker, and Redis, ensuring high availability and low-latency production responses.
- Established comprehensive evaluation frameworks and dashboards leveraging LangSmith and RAGAS, enabling continuous monitoring, rapid debugging, and improved reliability of LLM applications.
Machine Learning Engineer
Atypon Systems
- Architected a hybrid retrieval system (Elasticsearch) and integrated LLMs (Gemini, Llama) via LangChain and Self-RAG.
- Fine-tuned bi-encoders (MiniLM), boosting recommended article CTR by 100% and search CTR by 20%.
- Developed a comprehensive taxonomy and automated tagging system using deep learning transformers, leading to a 30% increase in Success Search Rate (SSR) and reducing manual tagging time by over 90%.
- Orchestrated high-performance model serving utilizing NVIDIA Triton Inference Server and optimized document processing pipelines with quantization and ONNX to ensure scalable, low-latency production inference.
- Implemented a real-time user profiling system from streaming event data to generate personalized promotions, driving a 300% increase in new user registrations and a 200% increase in authenticated sessions.
- Built testing pipelines to evaluate embedding retrieval (SciRepEval, BEIR) and continuously measure LLM faithfulness and answer relevancy using the RAGAS framework and LLM-as-a-judge techniques.
Machine Learning/Data Engineer
Self-employed
- Formulated a specialized RAG architecture using Elasticsearch, enabling highly accurate, hybrid search of influencer profiles for targeted brand campaigns.
- Created a scalable pipeline leveraging OpenAI APIs and Hugging Face models, streamlining the workflow for generating domain-specific educational materials.
- Designed an automated, end-to-end system for generating professional headshots, harnessing PyTorch and OpenCV, efficiently deployed via FastAPI and Docker.
Experience
Mininio
https://cogian.github.io/CoGian/mininio/Education
Master's Degree in Data and Web Science
Aristotle University of Thessaloniki - Thessaloniki, Greece
Bachelor's Degree in Applied Informatics
University of Macedonia - Thessaloniki, Greece
Certifications
Agentic AI MOOC (Legendary Tier)
UC Berkeley Center for Responsible, Decentralized Intelligence
Machine Learning in Production
DeepLearning.AI via Coursera
Deep Learning Specialization (5 Courses)
DeepLearning.AI via Coursera
Machine Learning
Stanford University via Coursera
Skills
Libraries/APIs
PyTorch, OpenCV, PubSubJS, PySpark, Scikit-learn, SpaCy, TensorFlow
Tools
Git, Apache Beam, Open Neural Network Exchange (ONNX), Apache JMeter, Cloud Dataflow, Docker Compose
Languages
Python, Java, Scala, C, Kotlin
Platforms
Docker, Databricks, LangSmith, Google Cloud Platform (GCP), Langfuse, Android
Frameworks
LangGraph, Apache Spark, Flask, LlamaIndex
Paradigms
REST, Microservices
Storage
Elasticsearch, Neo4j, Redis, PostgreSQL, MongoDB, MySQL
Other
Natural Language Processing (NLP), Hugging Face, LangChain, Agentic AI, FastAPI, Microsoft Azure, OpenAI, Pinecone, MLflow, CI/CD Pipelines, Maven, Explainable Artificial Intelligence (XAI), Transformers, Deep Learning, Software Development, Information Retrieval, Computer Science, Artificial Intelligence (AI), LLM Fine-tuning, Edge AI, Machine Learning, AI Agents, LLM Agents, Agentic Coding, Google ADK
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
Share your needs
Choose your talent
Start your risk-free talent trial
Top talent is in high demand.
Start hiring