MAREK SAGAN • JAVA / DEVOPS EXPERT Email (preferred) marek.sagan@protonmail.com Website https://mareksagan.github.io Projects https://github.com/mareksagan References https://www.linkedin.com/in/marek-sagan/ Availability Immediate

8 years of hands on web development and DevOps. Self driven, dedicated and problem solving software engineering professional. Passionate and creative about Object Oriented Programming software development

SKILLS Skills (years of experience) (8) Java, Spring Boot, Spring Framework, ReactJS, Redux, Amazon Web Services / AWS, Amazon Elastic Beanstalk, Amazon EC2 (5) C#, .NET, LINQ, React Hooks, AngularJS, VueJS, Single Page Application / SPA, SCSS, Material Design, Scrum, Git, Ansible, Maven, Java Database Connectivity / JDBC, JDK, Oracle Databases, Postgres, RDBMS, SQL / DML / DDL, Microsoft SQL Server, ASP.NET Core, MVC, Jenkins, Groovy, Apache Tomcat, Internet Information Services / IIS, Windows Communication Foundation, Python, PowerShell Scripting, Bash Scripting, XAML, SOAP, REST, Agile Development, Lean Methodology, IntelliJ IDEA, Visual Studio, Teamwork, Networking, Software Engineering, Communication Skills, Open Source, Microsoft Team Foundation Server / TFS, XML, JSON, Object Oriented Programming / OOP, Version Control Systems / VCS, Web Technologies, Microsoft Office, Microsoft Excel, Microsoft Teams, Information Technology / IT, Artificial Intelligence / AI, Data Science, Data Sources, Apache Spark, Apache Hadoop, AJAX, Microservices Architecture, Amazon Lambda, Google Cloud, Google App Engine, Alibaba Cloud, Ethereum blockchain, Kali Linux, Nessus, Aircrack-ng, Hashcat, Nmap, AWS Security Hub, Analytical Skills, Attention To Detail, Multicultural Understanding, Organizational Skills, Time Management Skills, Presentation Skills, Verbal Communication Skills, Interpersonal Skills, Collaboration, Apache Solr, IText, Elasticsearch, Negotiation Skills, Market Research, Search Engine Optimization / SEO, Wordpress, PHP, Jekyll, Integrity, Scala, Functional Programming (4) JUnit, XUnit, Unit Tests / Unit Testing, Acceptance Testing, Mockito, C, C++, R, Microsoft Dynamics CRM, Sitecore CMS, CSS, Bootstrap, Service Oriented Architecture / SOA, Test Driven Development / TDD, Docker, Kubernetes, Keycloak, Okta, Spring Security, TensorFlow, MongoDB, Redis, Express.js, Atlassian JIRA, Atlassian Confluence, Unified Modelling Language / UML, Product Design & Architecture, Leadership Skills, Kanban, Data Analytics, Ability To Work Independently, Ability to Prioritize, Mentorship Skills, Coaching Skills, Operations Research, Distributed Computing, Distributed Systems, Web Applications (3) JEE / J2EE, Eclipse, Stellar, Apache Kafka, Red Hat Drools, Business Rules Management / BPM, Windows Server, DevOps, OpenAI ChatGPT, Meta Llama, Spring AI, LangChain, LLM Hallucinations, RAG, Prompt Engineering, OpenAI Whisper, Kling AI, Generative AI, LoRA, image2image, video2video, text2image, text2video, image2video, Apache Airflow, PyTorch, scikit-learn, pandas, PySpark, Amazon EMR, Amazon Sagemaker, Snowflake, NLTK, NLP, Microsoft Azure, Wireshark, Metasploit, Domain Driven Design / DDD, Project Management Skills, Product Management Skills / PM, Quality Assurance / QA, Quality Engineering, Technical Support, User Experience / UX, Recruitment, Software Development Life Cycle / SDLC Methodologies, Technical Design, Product Development Certification Java SE 11 Developer, AWS Solutions Architect Associate, Microsoft Azure Fundamentals, Professional Scrum Master I, Prince2 Foundation, The Complete Prompt Engineering For AI Bootcamp, JavaScript: Understanding the Weird Parts, Machine Learning, Data Science and Deep Learning with Python, Apache Tomcat Server from Beginners to Advanced, Building Real-Time REST APIs with Spring Boot, Master Hibernate and JPA with Spring Boot, Apache Cassandra in 2 hours, Kafka & Kafka Stream for Java Spring Boot, Complete React Developer with Redux, Hooks and GraphQL, Ethereum: Decentralized Application Design & Development, Jakarta EE / Java EE Deep Dive, Complete Guide to Elasticsearch, Kotlin for Java Developers, Learn Test Driven Development in Java, Master Drools, RabbitMQ & Java Spring Boot System Integration, Master Spring Boot Microservices with CQRS & Even Sourcing, Data Visualization with Kibana, Dive Into Ansible, Git Complete, Introduction to Sparx Enterprise Architect, Learn JIRA with Real-World Examples, Learn JMETER From Scratch on Live Apps, Neo4j: GraphDB Foundations with Cypher, OpenAPI: Beginner to Guru, Kubernetes Certified Application Developer, Prometheus: The Complete Hands-On for Monitoring & Alerting, CI/CD with Jenkins using Pipelines and Docker, TOEFL, TestDaF Spoken languages English (fluent), German (fluent), Czech (fluent), Polish (native)

PERSONAL DATA Citizenship Poland (European Union) Interests Sports, health, climate change

WORK EXPERIENCE 01/2024 – 09/2024 Knappschaft – Bochum, Germany Lead Software Engineer – Contract • Developing new features and leading the team for the non-profit migrant and low income household supporting application (Java 21, JUnit, Spring Boot 3, Swagger / OpenAPI, Spring Cloud, Sleuth, OpenFeign, RabbitMQ) • Adjusting and extending processes and functions (AWS EC2, AWS S3, AWS CloudFormation, AWS CloudWatch, Ansible, Kubernetes, Jenkins) • Developed a PoC helpdesk AI agent (OpenAI ChatGPT, Meta Llama 3, OpenAI Whisper v2, FLUX.1, Kling AI, Spring AI, LangChain, LLM hallucinations, LlamaIndex, RAG, generative AI, LoRA, prompt engineering) • Maintaining and improving the existing microservices (Keycloak 17, Spring Security, AWS RDS)

03/2023 – 12/2023 Orange Poland – Warsaw, Poland Senior Software Engineer – Contract • Working on a sales authentication/authorization system with DevOps support (Java 17, JUnit, Groovy, Spock, Spring Boot, OpenAPI, Spring Cloud, WildFly, Flyway) • Adjusting and extending the security mechanisms and 2FA codebase (k8s, OAuth2, Keycloak) • Maintaining and improving the existing microservices (OWASP Top 10)

06/2022 – 03/2023 Circle K – Warsaw, Poland Senior Software Engineer – Contract • Developing new features for the remote fueling application (Java 17, JUnit, Groovy, Spock, Kotlin, Spring Boot, Spring WebFlux, Swagger / OpenAPI, Spring Cloud, Sleuth, OpenFeign) • Adjusting and extending pipelines and functions (Azure Kubernetes Service, Azure DevOps, Azure Functions, Azure Event Grid, Azure Event Hubs, Azure Cosmos DB) • Collaboratively maintaining and improving the NodeJS based microservices (NodeJS 16, TypeScript, HapiJS) • Close and strong cooperation with diverse multinational teams and overcoming outsourcing challenges such as complex bug fixing and missing documentation within available business capabilities

07/2021 – 06/2022 WorkFusion – Warsaw, Poland Senior Software Engineer – Contract • Using and improving Machine Learning algorithms for the core product (Java 8, Groovy, Scala) • Developing Proof of Concepts and working with multiple teams on advanced domain systems implementation, including the security team and vulnerabilities heuristics • Decoupling micro services to promote good separation of concerns in order to meet client expectations (Apache Zookeeper, RabbitMQ) • Service deployment and orchestration (Docker, Kubernetes, KubeFlow, Camunda BPM, JBoss Drools, Spring Boot Microservices, Feign, Keycloak, Apache Mesos, HashiCorp Vault, Marathon, HAProxy, Elastic Search, Kibana, Grafana)

05/2020 – 06/2021 Orange Poland – Warsaw, Poland Senior Software Engineer – Contract • Coding new features of and tuning the firmware / middleware on embedded systems (Java 7, ReactJS, Google Web Toolkit / GWT, Apache Kafka, Apache Zookeeper) • Involved in IoT / Internet of Things development of smart home entertainment solutions (MongoDB, Spring WebFlux) • Motivated help for juniors to grow based on trust and reputation and preparing high level internal training • Conducting performance analysis and performance tuning in the production environment

12/2019 – 04/2020 E.STRADIS GmbH – Augsburg, Germany Back End Engineer – Full-time • Developing new features of and tuning the credit risk management financial products running on low latency Linux systems (Java 7, Java EE, EJB, JMS, JDBC, JSP, Servlets, RMI, SOA, Spring 4, JavaScript, CSS, ExtJS, Atlassian JIRA, Apache Ant, SVN) • Involved in building and debugging the features with focus on the analytics and project management side according to the industry regulations and business requirements / standards compliance • Communication and proactively follow up on the solutions, maintaining partnerships with the management / customer representatives from the finance sector • Conducting performance analysis and performance tuning • Writing and updating technical documentation for improved customer experience • Participating in the digital transformation innovation of the company • Remote work experience in a dynamic environment

08/2019 – 12/2019 DHL International GmbH – Prague, Czechia Senior Software Engineer – Contract • Programming of a Big Data driven scheduling application loading data into global application designed to support the sales process using the cloud architectures / cloud computing / distributed computing and relational databases / data warehouse (Java 8, JDBC, Apache Tomcat, Spring Boot, Oracle 12g, Ehcache, HikariCP, Teradata Vantage, MyBatis, SQL Loader, Amazon Web Services S3, AWS SDK) • Delivering together with external vendors a high quality customers performance reporting application analysing and reporting operational logistics performance from a global to facility level including the target transit time (Java 8, Apache Tomcat, Spring Boot, Oracle 12g, Red Hat Enterprise Linux 7) • Working on a highly scalable enterprise software generating daily / weekly call plans (Java 8, Apache Tomcat, Spring Boot, Oracle 12g, Red Hat Enterprise Linux 7)

04/2019 – 08/2019 Broadcom Inc. – Prague, Czechia Full Stack Developer / IT Architect – Contract • Conducting innovative research and development of the new mainframe products and their APIs (Java 8, Lombok, Mockito, Spring Boot, SLF4J, JUnit, Jacoco, Jersey, Guava, Apache Velocity, Apache Commons, SonarQube, Endevor, IBM z/OS, Git) • Developing a modern Cucumber End To End integration testing suite (Cucumber JVM, Selenium, test automation) • Effectively creating a Jenkins Continuous Integration build pipeline including a front end validation (eslint) • Making impact on the technical debt and major deficiencies in the React front end which has enabled the project delivery and for the product to enter the MVP lifecycle phase • Leading the front end development and mentoring / training the junior team member (s) including code reviews and technical knowledge / technical skills transfer

04/2018 – 04/2019 Amaris Consulting – Prague, Czechia Consultant – Full-time • Developing a collaborative bidding platform (Java 11, Maven, Spring MVC, JUnit, Mockito, Hibernate / JPA, PostgreSQL, Angular 7, Protractor, NG-ZORRO, Node.js, Red Hat Enterprise Linux 7) • Developing a competitive and user supporting system with Artificial Intelligence capabilities • Using the Machine Learning algorithms and data structures / design patterns e.g. Strategy pattern according to the proactive business analysis • Improving the existing system according to the Clean Code best practices and technical requirements / performance requirements • Extending and troubleshooting the root cause of the problems of the existing web services used by mobile applications (Microsoft Azure) • Developing an automation script for parsing and collaborating with banking clients for data migration reasons using flexible banking specific frameworks (Python 2.7, Murex MX.3, OpenHFT, FIX / Financial Information Exchange, Red Hat Enterprise Linux 7) • Familiarity with financial engineering and trading systems through consulting services

EDUCATION 2014 – 2018 Warsaw School of Computer Science Computer Science, Bachelor of Science 2021 – 2022 Warsaw School of Computer Science IT Project Management, Postgraduate Studies 2023 – 2024 The Power Business School Master of Business Administration, MBA