Lukasz R.
Software Engineer
Experience
Jan 2024 - Jun 2025
1 year 6 monthsSoftware 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 monthsFull 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 monthsMidle-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 monthBack 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
NativeEnglish
AdvancedEducation
Oct 2012 - Jun 2016
Saigon International University
Bachelor's Degree · Computer Science · Ho Chi Minh City, Viet Nam
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