Mark Z.
Verified expert
Mark Z.
Verified expert
Top skills
Meet Mark āØ
A Back-End Developer with four years of professional experience building scalable web platforms and AI-driven systems. Mark specializes in Python-based backend development using FastAPI and Django, with strong expertise in SQL and NoSQL databases, AWS infrastructure, and distributed system design.
He has contributed to high-impact AI projects including a Retrieval-Augmented Generation application with vector database integration, a large-scale European information platform serving over 15 million pages, and an AI-powered blockchain security system. His work includes backend architecture improvements, event sourcing implementation, file and document processing pipelines, vector indexing, and performance optimization across complex systems.
Mark focuses on writing clean, maintainable code, improving system architecture, and ensuring backend reliability through unit testing and code review practices. With hands-on experience in Docker-based environments and cloud deployments on AWS, he delivers production-ready solutions built for scalability and long-term growth.
If you need a backend engineer who can combine AI integrations, database optimization, and structured architecture into stable and efficient systems, Mark is ready to strengthen your product š
Download the CVHard skills
Backend Architecture
Python
FastAPI
Django / DRF
SQLModel
SQLAlchemy
REST API Development
WebSockets
Event Sourcing
Vector Databases (Weaviate)
RAG Systems
Langfuse Integration
File & Document Processing
PostgreSQL
SQLite
MSSQL
Neo4j
Redis
Elasticsearch
AWS
Docker / Docker Compose
Minio
Gotenberg
Presidio
Aiohttp
Celery
Alembic
CI/CD (GitHub Actions)
Unit Testing (Pytest, Mock)
Tools
Git
GitHub
GitLab
Postman
PyCharm
Docker
Langfuse
Flowise
Minio
Soft skills
Responsibility
Reliability
Attention to detail
Analytical thinking
Team collaboration
Independent work
Continuous learning
Structured mindset
RAG Application
Back-End Developer
Project Description:
Built backend logic for a Retrieval-Augmented Generation system with vector database integration and docume
Tools & Technologies:
Python, FastAPI, SQLModel, Weaviate, Presidio, Minio, Docker.
European Information Platform
Back-End Developer
Project Description:
Maintained and improved architecture of a large-scale information system containing approximately 15 million pages. Focused on backend refactoring, API integrations, Elasticsearch performance tuning, and system scalability.
Tools & Technologies:
Python, FastAPI, PostgreSQL, Aiohttp, Elasticsearch, Docker.
AI-Security Platform
Back-End Developer
Project Description:
Developed backend services for blockchain threat detection platform using ML algorithms. Contributed to DB optimization, deployment scripts, and scalable API architecture.
Tools & Technologies:
Python, FastAPI, Neo4j, Redis, PostgreSQL, AWS, Docker.
Lublin University of Technology
Bachelorās Degree in Computer Science
FastAPI Masterclass
Provider: Udemy
FastAPI Masterclass
Provider: Udemy
Build REST APIs with DRF
Provider: Udemy
Build REST APIs with DRF
Provider: Udemy
AWS Cloud Practitioner
Provider: AWS
AWS Cloud Practitioner
Provider: AWS
Python Immersion
Provider: Coursera
Python Immersion
Provider: Coursera
Python Course
Provider: FoxmindEd
Python Course
Provider: FoxmindEd
This freelancer has not participated in any projects yet.
Python back end development
November 2025
"Working with Mark has been really great. He's a very talented and experienced developer and his contribution to our project was substantial. HIghly recommended!"
Python Expert with Fast API know-How
March 2025
"Working with Mark has been a great experience. Heās a talented developer who communicates tasks clearly and effectively. He takes initiative in solving complex problems and collaborates well with the team. His insights into our software design have been invaluable. Thank you for your dedication and hard work!"
Upgrade and extension of an existing Django web application
November 2024
"Mark did a good job on our project, and I appreciated working with him. His communication was clear, he met deadlines, and his skills were good. Overall, it was a good experience, and Iād likely work with him again in the future."
Create API endpoint for small Github code
June 2024
"Mark was not only able to help with the original help that I asked for, but even when I requested other unrelated help, he was still able to figure things out very quickly. I would highly recommend him to anyone looking for his skillset of work. He was very proficient in creating a github fork and guiding me on how to edit it and deploy it, to be accessed with an API call."
Integrate web search feature into chatbot Close the dialog
April 2026
"Mark is a pleasure to work with. Even if you give him something he may not be very familiar with, he'll still figure it out very quickly!"
Help researching LLM web search tools & programs
April 2024
"Mark completed the work very quickly, without cutting any corners. He does very good work in a very timely fashion."
