Recommended expert

Vitalii Paderin

Senior Full Stack Engineer

Vitalii Paderin
Warsaw, Poland

Experience

Jan 2021 - May 2025
4 years 5 months
Berlin, 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 3× 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 months
London, 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 months
Warsaw, Poland

Software Developer

Scalo

  • Developed Java-based SaaS, CRM, and fintech systems for agency projects, improving system performance for 10,000+ daily active users and 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 (a 3.4× improvement) 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.
  • 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.

Skills

  • Languages: Java, Python, Javascript, Go
  • Backend: Spring Boot, Spring Cloud, Java Ee, Quarkus, Fastapi, Django, Rest, Graphql, Grpc, Kafka, Rabbitmq, Redis, Ehcache, Micronaut, Openapi, Swagger, Junit, Testng, Spring Boot Test
  • Frontend: React.js, Next.js, Angular, Vue.js, Tailwind Css, Material Ui, React Native, Flutter, Kotlin, Swift, Chart.js, Redux, Redux Toolkit, Zustand
  • Testing: Junit 5, Testng, Spring Test, Restassured, Selenium, Jest, Postman
  • Databases: Mysql, Postgresql, Mongodb, Aws Dynamodb, Azure Cosmos Db, Jpa, Hibernate, Liquibase
  • Cloud & Devops: Aws (Ecs, Lambda, Sqs, Sns, S3, Rds, Api Gateway), Gcp, Kubernetes (Eks/gke), Docker, Helm, Terraform, Github Actions, Jenkins, Elk, Prometheus, Grafana
  • Monitoring & Logging: Cloudwatch, Elk Stack, Opentelemetry, Jaeger, Grafana, Distributed Tracing
  • Architecture & Patterns: Microservices, Event-driven Systems, Serverless, Cqrs, Ddd, Mdsd, Soa, Dsl, Monolith-to-microservice Migration, Mvvm, Dependency Injection (Di), Ssr, Mvc
  • Compliance & Protocols: Fhir, Hl7, Hipaa, Pci-dss, Websockets, Tcp/ip, Rest, Soap
  • Security: Oauth2, Jwt, Keycloak, Openid Connect, Saml, Ssl/tls, Rbac, Mfa, Azure Key Vault, Aws Kms
  • Ai/ml: Openai Api, Hugging Face Transformers, Tensorflow, Nlp, Pandas, Numpy, Shap, Mlflow
  • Tools & Workflow: Agile (Scrum, Kanban), Jira, Confluence, Bitbucket, Git, Intellij, Vs Code

Languages

English
Advanced
German
Intermediate

Education

Mar 2012 - Nov 2015

University of Warsaw

Bachelor of Science, Computer Science · Computer Science · Warsaw, Poland

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