Lukasz R.

Software Engineer

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Popowo, Poland

Experience

Jan 2024 - Jun 2025
1 year 6 months

Software Engineer

SoftTeco

  • Built Java Spring Boot microservices for real-time banking transactions and trading operations
  • Applied CQRS with MediatR-style patterns and event sourcing using EventStoreDB for consistency and auditability
  • Designed serverless, event-driven workflows using AWS Lambda, API Gateway, SQS/SNS, and DynamoDB, monitored via Datadog & CloudWatch
  • Developed REST, gRPC, and GraphQL endpoints with Spring Boot, handling high-concurrency transaction and reporting APIs
  • Implemented Spring AOP and custom annotations for cross-cutting concerns like logging, metrics, and auditing
  • Optimized PostgreSQL and Redis queries for low-latency access to transaction data; applied caching and indexing strategies
  • Integrated JWT, OAuth2, and AWS Cognito for secure RBAC-based authentication and authorization
  • Refactored Angular frontend using Reactive Forms, FormGroup/FormControl, patchValue/setValue, validators, and NgRx store with selectors, actions, and effects
  • Applied RxJS operators (combineLatest, pipe, map, filter) for reactive UI updates
  • Built background jobs and async processing pipelines with Spring Batch and Quartz for trade settlement and reporting
  • Deployed microservices to AWS ECS with Docker and Terraform, implementing blue/green deployments, auto-scaling, and high availability
  • Configured observability pipelines with ELK Stack, Datadog, and CloudWatch to monitor latency, errors, and throughput
  • Automated CI/CD pipelines with GitHub Actions and Jenkins, including linting, unit/integration tests, container builds, and rolling deployments
  • Wrote unit, integration, and E2E tests with JUnit, Mockito, and Karma/Jasmine, following TDD practices
  • Mentored junior developers, conducted code reviews, and collaborated across teams on API design and system architecture
Sep 2019 - Dec 2023
4 years 4 months

Full Stack Engineer

WarmElsa

  • Developed modern, responsive UIs using Angular (RxJS, NgRx) and TypeScript, integrated with APIs and third-party services
  • Built reusable Angular component libraries with Angular Material and SCSS, improving design consistency across apps
  • Designed and implemented RESTful and GraphQL APIs with Java (Spring Boot), serving high-traffic web applications
  • Integrated external services such as Stripe, Salesforce, and Twilio, enabling payments, CRM synchronization, and SMS/email notifications
  • Implemented AI-driven features like document summarization and semantic search using Java-based AI libraries and APIs
  • Built background job pipelines with Java (Spring Batch/Quartz) and Redis for asynchronous data processing and reporting
  • Deployed and scaled microservices on AWS ECS with Docker and Terraform, ensuring fault tolerance and auto-healing clusters
  • Implemented monitoring and logging with Datadog, ELK Stack, and AWS CloudWatch, enabling proactive incident response
  • Automated CI/CD workflows with GitHub Actions and Jenkins, adding linting, tests, and blue/green deployments
  • Optimized database queries in PostgreSQL using indexing and caching, reducing latency
  • Improved frontend performance through Angular lazy loading, route-based code splitting, and Lighthouse audits, boosting SEO rankings
  • Led code reviews and introduced TDD with JUnit, Mockito, and Jest, achieving 85%+ test coverage
  • Mentored junior developers and contributed to knowledge-sharing sessions, improving team delivery velocity
Jul 2017 - Aug 2019
2 years 2 months

Midle-level Full Stack Developer

Timspark

  • Built and maintained Angular frontends with NgRx and RxJS for complex state management
  • Developed backend services with Java (Spring Boot), exposing RESTful APIs
  • Implemented WebSockets and real-time APIs for chat, notifications, and collaborative tools
  • Designed PostgreSQL schemas with Hibernate/JPA ORM, optimizing queries for high-volume transactional workloads
  • Integrated OAuth2, JWT, and SAML authentication flows, enhancing platform security and compliance
  • Applied MFA and PKI encryption to sensitive data workflows, strengthening data protection
  • Containerized applications with Docker and deployed them in Kubernetes clusters, enabling horizontal scaling
  • Automated CI/CD pipelines with Jenkins and GitLab CI, including unit tests, integration tests, and container builds
  • Introduced Sentry and Prometheus for performance monitoring and error tracking
  • Integrated social media APIs (Facebook, LinkedIn) for analytics aggregation dashboards
  • Implemented blockchain-related features including Solidity smart contracts and wallet integrations (MetaMask, WalletConnect)
  • Developed mobile and desktop apps with Ionic and Electron, extending platform reach
  • Adopted TDD with JUnit, Mockito, and Jest, reducing regression bugs by 30%
  • Collaborated with Agile teams using Jira, Scrum ceremonies, and sprint planning, contributing to continuous delivery
Jun 2016 - Jun 2018
2 years 1 month

Back End Developer

uCloud

  • Developed backend services using Java (Spring Boot), with PostgreSQL and MySQL as primary databases
  • Built and maintained REST APIs for internal services and external client integrations
  • Containerized services with Docker and deployed to AWS Elastic Beanstalk
  • Collaborated with frontend teams to integrate APIs into interactive dashboards
  • Participated in Agile sprints, contributing to code reviews, testing, and documentation

Summary

Full Stack Engineer with 8+ years of experience building cloud-native, secure, and scalable applications.

Skilled in Java (Spring Boot), Angular, TypeScript, microservices, and real-time/event-driven systems.

Experienced in AWS, CI/CD, observability, and TDD. Strong in performance optimization, domain-driven design, and mentoring agile teams.

Languages

Vietnamese
Native
English
Advanced

Education

Oct 2012 - Jun 2016

Saigon International University

Bachelor's Degree · Computer Science · Ho Chi Minh City, Viet Nam

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