Vitalii P.
Senior Full Stack Engineer
Experience
Jan 2021 - May 2025
4 years 5 monthsBerlin, Germany
Senior Full Stack Engineer
Ada Health
- Spearheaded an AI-powered patient-facing healthcare management system using Python, Java 17, Spring Boot, Angular and Hibernate, reducing patient registration time by 40% through streamlined workflows.
- Migrated legacy monolithic EMR application to a microservices architecture, enhancing system scalability and reducing deployment time by 60%.
- Integrated Python FastAPI microservices with the healthcare platform to serve real-time predictive analytics, ensuring sub-second response times for clinical dashboards.
- Implemented secure RESTful APIs with Spring Security, JWT, and OAuth 2.0, ensuring HIPAA compliance and improving access control auditing by 100%.
- Integrated with FHIR and HL7 standards using HAPI-FHIR and Mirth Connect to enable seamless data exchange with third-party EHR systems, covering 90%+ interoperability use cases.
- Leveraged Apache Kafka for real-time lab result processing and notifications, achieving 3x faster delivery of critical patient updates to physicians.
- Engineered a conversational mental health assistant powered by Python NLP pipelines and OpenAI API, handling 10,000+ weekly queries and deflecting 35% of routine support requests.
- Built custom medication tracking modules with barcode integration, developing smart alerting algorithms and patient-facing mobile interfaces that increased medication adherence monitoring by 35%.
- optimized complex SQL and JPQL queries in PostgreSQL, reducing report generation latency by 45% through indexing and query tuning.
- Engineered role-based access control (RBAC) with Spring Security and LDAP integration, ensuring secure multi-role access across administrative and clinical users.
- Utilized Jenkins, Docker, and Kubernetes to automate CI/CD pipelines and streamline deployment to on-prem and cloud environments, improving deployment reliability by 70%.
- created interactive, real-time dashboards with React and D3.js for clinicians to monitor patient vitals and analytics, contributing to a 25% improvement in decision-making speed.
- Applied Test-Driven Development (TDD) using JUnit, Mockito, and TestContainers, increasing test coverage to 85% and reducing post-release bugs by 50%.
- Integrated Python ML models into the React frontend via REST APIs, enabling instant feedback loops for exercises like mood tracking and journaling.
- Participated in Agile ceremonies (sprint planning, retrospectives, daily standups) and led backlog refinement sessions, contributing to consistent 95%+ sprint delivery rate.
- Collaborated in Agile teams, conducted code reviews, and mentored junior engineers, contributing to a 25% increase in team velocity and overall code quality.
Jun 2018 - Oct 2020
2 years 5 monthsLondon, United Kingdom
Java Software Developer
Xeven Solutions
- Launched scalable backend systems for a high-traffic eCommerce platform using Java, Spring Boot, and MySQL, supporting over 80,000+ monthly active users.
- Generated microservices architecture to handle catalog, inventory, and order processing services, improving deployment flexibility and reducing service downtime by 70%.
- Achieved a mobile-first, responsive shopping interface using React.js, TypeScript, and Material-UI, integrated with FastAPI REST endpoints, increasing session duration and user engagement by 25%.
- Composed Apache Kafka for real-time order events, reducing cart abandonment and improving transaction traceability by 40% through asynchronous messaging and retry strategies.
- Combined secure RESTful APIs for checkout, payment, and order tracking with Spring Security, implementing JWT authentication and OAuth 2.0, reducing fraud incidents by 30%.
- Revised product search and filtering using Elasticsearch, improving search response time by 50% and increasing user engagement metrics across mobile and web.
- Organized Redis-based caching for product details and user sessions, reducing backend load by 60% during peak traffic events like Black Friday and flash sales.
- Revised containerized services using Docker and Kubernetes on AWS EKS, with auto-scaling and failover, ensuring 99.99% uptime during high-demand periods.
- Automated CI/CD pipelines with GitHub Actions and AWS CodePipeline, enabling faster releases and reducing manual deployment errors by 80%.
- Enhanced system observability with Prometheus, Grafana, and ELK stack across 3 microservices, enabling real-time monitoring of container resource utilization and reducing average issue detection time by 45%.
- Achieved the development of real-time admin dashboards with React, TypeScript, and Chart.js, visualizing sales trends, inventory movement, and user behavior in real time.
- Established a responsive React Native mobile app for shopping, order tracking, and notifications, boosting mobile conversion rate by 35%.
Apr 2016 - Feb 2018
1 year 11 monthsWarsaw, Poland
Software Developer
Scalo
- Developed Java-based SaaS, CRM, and fintech systems, improving system performance for 10,000+ daily active users, ensuring seamless customer experience through optimized backend services.
- Introduced a micro-payment gateway using Spring Boot, Spring Security, OAuth2, and JWT authentication, reducing transaction failures by 25% and improving payment reliability.
- Designed and implemented batch-processing jobs using Spring Batch and Quartz Scheduler, automating financial data processing and cutting manual workload by 50%, improving operational efficiency.
- Redesigned SQL queries and Hibernate configurations in PostgreSQL, reducing query response times by 20% and enhancing database performance.
- Reduced music search response times from 1.8 seconds to 0.5 seconds by leveraging Elasticsearch for advanced indexing strategies, improving user search experience.
- Developed RESTful APIs using Spring MVC and GraphQL with Apollo Server, enhancing data-fetching efficiency and improving frontend-backend communication for dynamic user interfaces.
- Integrated third-party payment APIs (Stripe, PayPal, Plaid) into systems, streamlining transaction workflows and enhancing user payment experience with seamless integrations.
- Built real-time event-driven microservices using Apache Kafka and WebSockets, improving system responsiveness and reliability during peak usage periods, ensuring real-time data processing.
- Integrated Micrometer with Spring Boot Actuator to expose real-time metrics for Prometheus, improving system observability and proactive issue resolution across microservices.
- Automated CI/CD pipelines using Jenkins and Docker, improving deployment speed and system stability across multiple environments, ensuring a consistent delivery process.
Summary
Java Software Engineer with over 10 years of experience designing and enhancing enterprise-level solutions. I thrive on solving complex challenges and delivering results-driven software. My expertise includes Java, Spring Boot, Java EE, Python, SQL, React, Angular, AWS, Kubernetes, Kafka, and AI integration.
Languages
English
AdvancedGerman
IntermediateEducation
Mar 2012 - Nov 2015
University of Warsaw
Bachelor of Science · Computer Science · Warsaw, Poland
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