Олександр

Oleksandr Lazarenko
Full Stack Software Engineer
+(380)-95-012-258 @ [open contact info](look above in the "contact info" section) in/olexandr-lazarenko/

SUMMARY EDUCATION
A knowledgeable and passionate software engineer with more than 4 years of experience in Master of Science, Software Engineering
making awesome projects for even more awesome businesses.
Kharkiv National University of Radio Electronics
A proud author of the "Node.js Security Unleashed" article series on Medium & Hashnode н 09/2024 - Present 9 Kharkiv, Ukraine
platforms.
Bachelor of Engineering, Computer Science
PROFESSIONAL EXPERIENCE V. N. Karazin Kharkiv National University
ш 09/2020 - 08/2024 Q Kharkiv, Ukraine
Middle Back End Engineer
ELEKS : Federated GraphQLAPI gateway for e-Commerce Aggregator SKILLS
н 06/2024 - 01/2025 Q Remote
• Implemented a centralized Backend-for-Frontend (BFF) gateway using Node.js and Front End Development
Apollo Federation, significantly improving the front-end team's productivity by simplifying
API integration and reducing time-to-market for new client-side features. HTML CSS JavaScript TypeScript
• Enhanced overall system efficiency by optimizing database queries, implementing
advanced indexing strategies (incl. partial & covering indexes) and applying data
SASS React.js GraphQL (Apollo) PWA
partitioning techniques to eliminate performance bottlenecks.
• Developed a near real-time Kafka CDC ingester, which synchronized operational data to
a Hadoop Distributed File System (HDFS) sink for further behavioral analysis. SSR (React) Next.js(13+) Webpack
• Improved internal monitoring and observability platform by moving from custom
distributed tracing protocol to OpenTelemetry, allowing automatic code instrumentation
and enabling operational team to quickly adapt to system errors. Back End Development

Middle Full Stack Engineer Node.js Nest.js .NET Core ASP.NET
InBase [Intecracy Group] :
Governmental Document Management System (DMS) GraphQL (incl. federation) RESTfulAPI MSA
Ш 07/2023 - 05/2024 Q Remote
• Curated and successfully finished the incremental migration of a legacy Ext JS based
DevOps Stack
document management system to React 17, enhancing maintainability and eliminating
significant licensing costs.
• Designed and implemented a custom React server-side rendering (SSR) engine with GitLab AWS Docker Kubernetes
selective markup hydration support, which led to greatly reduced page load time and
facilitated a feature-oriented migration process. Helm Prometheus Grafana Loki Nginx
• Set up fully automated CI/CD pipelines using self-hosted GitLab cluster for both back-end
and front-end modules, ensuring their adherence to defined performance service level
objectives (SLOs). Data Management
• Addressed a critical issue related to concurrent document modifications in a distributed
system by implementing a custom coordination strategy based on Zookeeper, ensuring PostgreSQL (13+) MySQL Redis Kafka
data linearizability and eliminating database cluster conflicts.

Front End Engineer RabbitMQ Elasticsearch MongoDB Flink

NIX Solutions : Offline-first collaborative editing Software
Й 11/2022 - 05/2023 Q Kharkiv, Ukraine
• Proactively contributed to defining the project's service-level indicators (SLIs) and took NOTABLE CERTIFICATION
key decisions regarding the overall project structure and architecture.
• Developed a comprehensive web design system, including core styling primitives and AWS Certified Cloud Practitioner
flexible component templates, enhancing both developer experience and overall user AWS - Official exam (acq. 2023, valid thru April 2026)
satisfaction.
• Implemented an offline-first, mobile-compatible collaborative text editor using delta-based
Conflict-free Replicated Data Types (CRDTs) and Service Worker-based synchronization LANGUAGES
to handle offline editing and conflict resolution.
• Regularly held intra-corporate presentations to share updates on the team’s
achievements, technological advancements and findings, enabling knowledge sharing
Ukrainian Native speaker • ••••
and cross-functional collaboration.
English Proficient • •••
Junior Full Stack Developer
SoftServe : Web Platform for taking online proctored exams VOLUNTEERING
05/2022 - 10/2022 Q Remote
Streetcode project (https://streetcodes.in.ua/)
• Tackled numerous technical debt issues through rigorous debugging and code
optimization, leading to noticeable application performance improvements and SoftServe [OpenTech initiative]
enhancement of overall user satisfaction. щ 11/2022-01/2023
• Created exhaustive test suites of the application codebase and established a strict Cl- • Played a pivotal role in development of one of the
passing framework, achieving 90% test coverage and meeting expected SLO values.
(as of 2025) largest Ukraine’s historical platform,
• Maintained a legacy high load web application, driving its gradual migration to a modern
contributing to both technical and organizational aspects.
tech stack, including the transition from self-hosting infrastructure to public AWS cloud
• Delivered the MVP from initial concept to completion within
and PaaS Kubernetes deployment.
two months during the Ukraine armed conflict.
• Successfully containerized an N-tier application and deployed it to AWS Kubernetes • Facilitated productivity by creating internal documentation,
Service (EKS), greatly improving its scalability and deployment efficiency.
enabling efficient onboarding for new volunteers.