Marcus Pop, Developer in Timișoara, Timiș County, Romania
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Marcus Pop

Verified Expert  in Engineering

Back-end Developer

Timișoara, Timiș County, Romania
Toptal Member Since
January 31, 2022

Marcus is a passionate software engineer with 4+ years of experience working with infrastructure payment systems and enterprise software. He has worked on different projects and developed competencies in agile development and software design principles. As a believer in lifelong learning, Marcus is pursuing a Master's degree in AI and distributed systems and is eager to embrace new challenges that allow him to apply the knowledge he is now acquiring.


Wise Systems International
Java, Amazon Web Services (AWS), Keycloak, Springbot, JSON Web Tokens (JWT)...
Java, Django, Python 3, Apache Airflow, Kubernetes, Cloud Computing, SQLAlchemy...
IDEA Center at the University of Notre Dame
Java, Spring Boot, WebSockets, API Integration, Spring Security...




Preferred Environment

Visual Studio Code (VS Code), IntelliJ, Google Meet, Jira, GitLab, Postman, Java, Python, MacOS, MacBook

The most amazing...

...solution I've developed is a home assistant's dialogue manager, incorporating a knowledge-based system, command interpreter, and interface for external APIs.

Work Experience

Senior Software Engineer

2022 - PRESENT
Wise Systems International
  • Ensured real-time communication between different services and clients using AWS SQS, AWS Lambda, REST APIs, and websockets.
  • Modeled various entities to capture the game state and economy using PostgreSQL, Liquibase, and Hibernate.
  • Implemented security using Keycloak, JWT, OAuth-based authentication, and Spring Security.
  • Ran Monte Carlo simulations to simulate in-game loot-dropping probabilities.
  • Created integration and unit testing for various parts of the system.
  • Worked as senior Java back-end engineer on an NFT gaming platform where users can create and upgrade their avatars and mint them on the blockchain. Helped the team to prepare for the MVP release in June.
Technologies: Java, Amazon Web Services (AWS), Keycloak, Springbot, JSON Web Tokens (JWT), Message Queues, Hibernate, Monte Carlo Simulations, Mockito, Spring Data JPA, REST, REST APIs, Liquibase, Unit Testing, JSON, Object-oriented Programming (OOP)

Software Engineer Contractor

2022 - 2023
  • Added different processing endpoints, reviewed features, and created unit and integration tests.
  • Worked on a solution for seamless cloud data migration and integration across different vendors.
  • Worked on improving a data orchestration (built on top of Airflow) platform that transfers data between cloud platforms.
Technologies: Java, Django, Python 3, Apache Airflow, Kubernetes, Cloud Computing, SQLAlchemy, Docker, Databases, Django ORM, Flask-RESTful, Flask, Celery, Data, MySQL, Restify, REST, Middleware, Message Queues, Unit Testing, Spring, API Development, Springbot, REST APIs, JSON, Object-oriented Programming (OOP)

Java Developer

2022 - 2022
IDEA Center at the University of Notre Dame
  • Integrated Jira and GitHub external APIs into the application logic and tested those integrations using unit testing and mocked data. Created APIs to extend existing user flows and to be used for support and by front-end clients.
  • Helped the team with various security issues, such as securing the stateless authorization system based on JSON Web Tokens using HTTP cookies.
  • Improved the system architecture and readability and reduced the boilerplate code by implementing code practices specific to Spring Boot applications.
  • Assisted the team in implementing a customizable email-based notification service.
Technologies: Java, Spring Boot, WebSockets, API Integration, Spring Security, Spring Web Services, JSON, Cookies, JUnit, Mockito, Unit Testing, Java 11, Relational Databases, Integration Testing, Git, MySQL, Flyway, Postman, API Architecture, OpenAPI, Swagger, Spring, Databases, Jira REST API, REST APIs, GitHub, Back-end, API Development, API Testing, JPA, Spring Data JPA, Google Cloud Platform (GCP), Springbot, Object-oriented Programming (OOP)

Python Developer

2022 - 2022
Ordinal LLC
  • Created scripts to automate training data generation, parsing, cleaning, and formatting.
  • Researched and used algorithms for pattern matching. Cleaned and extracted information from data to be used by NLP models.
  • Implemented rules based on the output of deep learning models using spaCy and existing modules.
Technologies: Python, Azure, Generative Pre-trained Transformers (GPT), GPT, Natural Language Processing (NLP), SpaCy, Git, Data Processing, Algorithms, Tree Structures, Object-oriented Programming (OOP)

Software Engineer

2019 - 2022
  • Developed instant payment systems that allow banks' clients to send and receive money in almost no time. Worked on existing projects and different country-level implementations to add new features and requirements.
  • Prototyped an automation tool that allows developers to record themselves while navigating and using a web application and replicate that flow in a test environment to ease front-end application testing.
  • Created a tokenization algorithm with an instant payment system to hide sensitive card information. It uses a surrogate that is also Luhn-compliant instead of the actual account number.
  • Developed the back end for an eWallet application connected to the national banking infrastructure via the instant payments system. Automated the clearinghouse, tokenization system, and central banking system.
Technologies: Java 8, Apache Kafka, Hibernate, Spring Boot, Linux, REST, PostgreSQL, Back-end, APIs, Unit Testing, Distributed Systems, Selenium, Web Development, JavaScript, CSS, HTML, Integration Testing, Mockito, SSH, VM, Relational Databases, Git, Bash Script, Bash, Postman, Microservices, Spring, Databases, Back-end Architecture, Microservices Architecture, Reporting, Push Notifications, API Development, JPA, Spring Data JPA, Springbot, REST APIs, JSON, Object-oriented Programming (OOP)

Software Engineer Intern

2018 - 2019
National Instruments
  • Took part in the FPGA team that developed LabView NXG, a symbolic programming interface and environment used for developing engineering and research solutions that are meant to run on configurable hardware.
  • Cooperated with the main team to integrate and test new features and maintain and fix previously written code.
  • Learned agile development and enterprise software design principles and procedures as part of my internship.
Technologies: C#.NET, LabVIEW, VHDL, Windows Presentation Foundation (WPF), FPGA

Mobile Payment Application

Contributed to a digital wallet application connected to the national banking infrastructure through the Automated Clearing House and instant payments, tokenization, and central banking systems.

My responsibilities involved:
• Implementing various endpoints.
• Building the data model layer.
• Developing an administration system for multiple entities using the four-eyes principle.
• Creating a one-time password system for logging in.
• Assisting with designing and creating the KYC back-end flow for the mobile application.
• Connecting various systems to our back end.

Home Assistant Dialogue Manager
I implemented a dialogue manager module inside a currently in-development minimalistic voice assistant application. It enables users to communicate with it in Romanian and issue simple voice commands. The dialogue manager is a component inside the project for interpreting given commands and their parameters, deciding whether they are correctly specified or not; retrieving information from APIs, such as the weather or calendar; and issuing a meaningful response based on a given input.

Microsoft Imagine Cup 2019 Entry
I implemented a web application for the Microsoft Imagine Cup 2019 using Node.js and Azure. The application intends to give performance feedback to educators teaching children with disabilities. This feedback is based on emotion detection and analysis of incoming heart rate data and allows educators to create a lesson plan based on acquired and interpreted data.

Computer Vision Thesis

Implemented various models for semantic segmentation using UNet and Fast-SCNN and trained them on the Cityscapes Dataset to improve instance-based segmentation. Used other deep learning models, such as Mask R-CNN and Deep SORT, to construct an end-to-end computer vision pipeline to segment and track people from video files.

COVID-19 Patient Survival Prediction
Preprocessed a raw dataset about early COVID-19 patient data, visualized it, and applied different methodologies to deal with unbalanced data to classify the disease outcome using logistic regression.

Fraud Detection

A data science project aimed to classify fraudulent transactions given an unbalanced publicly available dataset. Had to engineer a lot of new features and clean and deal with missing data. I also had to construct plots and measure statistics to draw insight from the dataset. Finally, I have built several classification models to find the best one for the task (neural networks, decision trees, and logistic regression).

Microservices Authentication and Authorization Using Keycloak

I designed and implemented the authentication between two microservices and RESTful APIs using Keycloak. The application was deployed using Docker Compose and a common network. Requests were made using OpenFeign for easier declarative API calls, and the security was handled using Spring Security and Spring OAuth 2.

LLM Chatbot Integration

Integration of OpenAI's ChatGPT API in existing chats for document-based tasks using available SDKs, Langchain, and AWS. The final purpose is to create a plug-and-play solution that can easily be integrated into various existing popular chat systems (Slack, Microsoft Team, Mattermost), available through a monthly subscription.


Java, Python, Python 3, SQL, Java 8, JavaScript, HTML, R, C#.NET, VHDL, Prolog, CSS, Java 11, Bash Script, Bash


Hibernate, Spring Boot, JPA, Selenium, Spring Security, Mockito, Swagger, Spring, OAuth 2, Vanilla JS, Windows Presentation Foundation (WPF), JUnit, Django, Flask, JSON Web Tokens (JWT)


REST, API Architecture, Object-oriented Programming (OOP), Java Patterns, Unit Testing, Data Science, Microservices, Back-end Architecture, Microservices Architecture, E2E Testing


JSON, Spring Data JPA, PostgreSQL, Relational Databases, MySQL, Databases


Architecture, APIs, API Integration, Springbot, Enterprise Application Design, Computer Science, Artificial Intelligence (AI), Distributed Systems, Machine Learning, Deep Learning, Convolutional Neural Networks, Neural Networks, Back-end, Knowledge Bases, Natural Language Processing (NLP), Web Development, Image Processing, Data, Spring Web Services, Data Engineering, Feign, Generative Pre-trained Transformers (GPT), MacBook, LangChain, Chatbots, Chatbot, ChatGPT, Cloud Computing, Computer Vision, Algorithms, Computational Logic, Distributed Architecture, Optimization, FPGA, Facial Recognition, Object Detection, Image Segmentation, Artificial Neural Networks (ANN), Finite-state Transducers (FST), WebSockets, Cookies, Integration Testing, Data Processing, Tree Structures, SSH, VM, Google BigQuery, Know Your Customer (KYC), Reporting, Push Notifications, Authentication, Authorization, GPT, Middleware, Message Queues, API Testing, Monte Carlo Simulations


TensorFlow, Pandas, NumPy, REST APIs, Keras, API Development, Liquibase, Node.js, SpaCy, OpenCV, Scikit-learn, JOOQ, SQLAlchemy, OpenAPI, Jira REST API, Django ORM, Flask-RESTful, Restify


Git, Gradle, LabVIEW, Flyway, Postman, Apache Airflow, GitHub, Docker Compose, Keycloak, Celery


Amazon Web Services (AWS), Apache Kafka, Linux, Azure, Raspberry Pi, Kubernetes, Docker, Backendless, MacOS, Firebase, Google Cloud Platform (GCP)

2021 - 2021

Progress Toward a Master's Degree in Artificial Intelligence and Distributed Computing

West University of Timișoara - Timișoara, Romania

2017 - 2021

Bachelor's Degree in Computer Science

Technical University of Cluj-Napoca - Cluj-Napoca, Romania


TensorFlow Developer Certificate



DeepLearning.AI TensorFlow Developer

DeepLearning.AI, via Coursera


Deep Learning Specialization

DeepLearning.AI, via Coursera