Freelancer profile translated to English.
Back to original languageAbout Renis
Technically skilled. Solution-oriented. Future-thinking.
I am a Lead Full-Stack Software Developer with over 8 years of experience in the conception, development, and maintenance of complex software solutions – from internal enterprise applications to publicly accessible web and mobile platforms. My focus is on high-performance, maintainable architectures based on Java/JavaEE/Spring, Angular, Flutter, JavaFX, Node.js, as well as modern cloud and DevOps technologies.
What sets me apart: A high degree of technical depth combined with a strategic understanding of business processes. I quickly familiarize myself with new projects, work efficiently in a team or independently – and deliver scalable solutions with clean code and a well-thought-out structure.
Technical Focus & Strengths:
- Full-Stack Development: Spring Boot, JavaEE, Angular, JavaFX, Node.js, Flutter
- API Design & Integration: REST, SOAP, Kafka, Camunda BPM
- Databases: PostgreSQL, MySQL, MongoDB, H2, Flyway, Liquibase
- Security & Authentication: Spring Security 6, JWT, mTLS, Role-Based Access Control
- DevOps & Deployment: CI/CD with Jenkins, Docker, Kubernetes, Heroku, GitOps
- Cloud & Infrastructure: Google Cloud, Azure, Microservice Architecture, Load Balancing
- PDF & E-Invoicing: Dynamic document generation with OpenPDF, ZUGFeRD-compliant invoices
- Agile Methodologies: SCRUM, JIRA, Confluence – as well as direct collaboration with business departments
- UX/UI: Frontend architecture with Angular & Flutter, accessible interfaces (WCAG 2.1, ARIA)
- Technological Curiosity: Enthusiastic about modern concepts like Virtual Threads, Reactive Programming, Rust & C++ Interop
Industry Know-how:
- Insurance & Claims Management
- Real Estate Management
- Public Sector & Justice
- Education & Research
- Tourism & Booking Platforms
- Gastronomy
German
Native or bilingual
English
Fluent
Can work on-site
Bad Homburg vor der Höhe (up to 50km)
Experience
- Union Reiseversicherung AG (URV)Lead Full-Stack Software Developer & Technology StrategistApril 2025 - Today (1 year and 2 months)
PROJECT DESCRIPTION
This Dual-Platform project involves the continuous development and modernization of the digital infrastructure of Union Reiseversicherung:• Internal IBE: A legacy Struts-based insurance system used by company employees. The system is being completely rebuilt with Spring Boot and Thymeleaf, and modern database optimization strategies are being implemented.• Customer Booking Portal: A public platform for purchasing insurance and making payments. Accessibility is ensured by strict adherence to WCAG 2.1 and the legal requirements of the BFSG.TASKS & CHALLENGES
• Modernization of Legacy SystemsRe-development of a Struts-based backend system with Spring Boot and Thymeleaf.Modernization of code and refactoring of outdated data models to improve maintainability and performance.• Database Optimization & MigrationImplementation of schema refactoring and versioning with Liquibase.Optimization of queries and redesign of indexes to improve database performance and consistency.• Public, Accessible PlatformDevelopment of a responsive, accessible platform for customer bookings in accordance with WCAG 2.1 and BFSG requirements.Integration of secure online payment methods and multi-language functionalities.• Strategic LeadershipConsulting on tools, frameworks, security aspects, and future-proof infrastructure.Leading full-stack development processes from UI/UX to backend optimization. - Bundesagentur für Arbeit (BA)Lead Back-End Software DeveloperPUBLIC SECTORMay 2023 - April 2025 (1 year and 11 months)
PROJECT DESCRIPTION
Within the AIDAV project (Automation in Unemployment Insurance), I was significantly involved in the development and implementation of various components within the Customer Center and Operational Service domains.A particular focus was on the first project phase: the "Processing Readiness" component. The goal of this phase was to automatically check and prepare online applications for unemployment benefits. Only when an application was complete and correct was it assigned to Operational Service for processing.TASKS & CHALLENGES
• Process Automation with CamundaConception and maintenance of BPMN workflows in Camunda BPMN Engine.Implementation of robust error handling and fallback scenarios for stable process executions.• Service IntegrationRealization of cross-service communication via Kafka, REST, and SOAP.Ensuring smooth, event-based data exchange between microservices.• DevOps & DeploymentResponsible for CI/CD processes with Jenkins, Bitbucket, and Kustomize.Execution of production deployments as well as monitoring and fine-tuning of Kubernetes configurations.• Collaboration & Agile MethodsClose collaboration with business departments and stakeholders to validate business processes.Use of agile methods (SCRUM), progress management via JIRA, and documentation in Confluence. - Refin UnlimitedLead Full-Stack Software DeveloperNovember 2024 - Today (1 year and 7 months)
PROJECT DESCRIPTION
The Invoice Manager is a custom-developed web application for automating quote and invoice creation – specifically tailored to the needs of freelancers. The application is based on Vaadin and Spring Boot, combining a modern user interface with a secure, scalable backend.The platform enables the generation of legally compliant PDF invoices (including ZUGFeRD standard), management of customer data, and tracking of payment transactions. It was designed as an efficient tool for the daily work of freelancers.TASKS & CHALLENGES
• Professional Invoice & Quote CreationGeneration of structured PDF documents with OpenPDF, including company-specific branding and legally required fields. Including ZUGFeRD-compliant e-invoicing data for digital processing in accounting software.• Payment Status & DunningImplementation of a complete lifecycle for tracking payments, including reminder logic and history.• Customer & Contact ManagementPersistent maintenance of master customer data for recurring transactions and automated document creation.• Security & Data ProtectionSecure user login and data encryption according to best practices with Spring Security 6.• DevOps & DeploymentContainerization of the application with Docker for easy local and production deployment, including service networking.
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Education
- Master of ScienceFrankfurt University of Applied Sciences2022Master of Science in "High Integrity Systems"
- Master of ScienceUniversity of Tirana|2020Master of Science in "Informatik"