Oleksii

Oleksii Volyk
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Profile Senior Full-Stack Developer with 6.5 years of experience in the TypeScript ecosystem (Node.js,
NestJS, React), with hands-on experience building and deploying event-driven backend
services on AWS (Lambda, EventBridge, SQS, Step Functions). I take ownership of features
end-to-end, from architecture and estimation through deployment and CI/CD, and have
exposure to AI-assisted components (RAG, vector search) in production systems.

Skills Languages & Frameworks: TypeScript, JavaScript, Node.js, NestJS, React, Redux Toolkit,
Express, MaterialUI.
Cloud & Infrastructure: AWS (Lambda, ECS, S3, EventBridge, SQS, Step Functions, RDS,
Cognito), Kafka, GitHub Actions (CI/CD).
AI & LLM Integration: RAG (Retrieval-Augmented Generation), OpenAI API, vector
search (Amazon OpenSearch), LLM-based classification.
AI-Assisted Development: Built custom Claude skills and configured MCP integrations
(Slack, Jira, Git) to streamline daily development workflow.
Data & Databases: PostgreSQL, Prisma, TypeORM, MongoDB, DynamoDB, Redis
Testing & Tools: Jest, React Testing Library, Postman.

Work experience
July 2024 - Senior Full-Stack Developer
September 2026 Devico Solutions
Tech Stack: TypeScript, Node.js, NestJS, Prisma, PostgreSQL, React, Redux Toolkit, AWS
(Lambda, Step Functions, SQS, EventBridge, S3, DynamoDB, RDS, ECS), OpenAI API, Amazon
OpenSearch (vector search/RAG).

Key Projects & Impact:

Full-Stack Feature Delivery: Built and maintained core features across the stack (React
frontend, NestJS backend) for a SaaS platform that automates carbon emissions
calculations for regulatory reporting.

Serverless Backend Architecture: Built event-driven backend services on AWS (Lambda,
Step Functions, ECS, SQS, and EventBridge), enabling reliable and asynchronous data
processing at scale.

Data Pipeline & Validation: Owned the pipeline for large customer datasets end-to-end,
from S3/DynamoDB-backed ingestion through complex validation logic, ensuring data
accuracy for regulatory compliance.

AI-Assisted Data Classification: Contributed to a hybrid pipeline using LLM classification
and reference-data search to match customer data with regulatory standards,
significantly improving accuracy compared to manual matching.

November 2023 - Middle+ Full-Stack Developer
May 2024 UKEESS
Tech Stack: JavaScript, TypeScript, React, Node.js, Redux Toolkit, Webpack, Jest.
Key Projects & Impact:

Search Functionality Modernization: Worked on a major technical transition for the
Ancestry project, focusing on refactoring and rewriting legacy search widgets into a
modern tech stack.

Feature Improvements & Migration: Translated Figma designs into high-quality React
components while ensuring all business logic was correctly migrated from the older
system.

Complexity Research: Spent significant time reverse-engineering older parts of the
application to understand hidden complexities, allowing for more accurate task
estimation and smoother transitions.

June 2021 - Middle+ Full-Stack Developer
October 2023 MEV LLC
Tech Stack: TypeScript, Node.js, Express, React, Redux, MongoDB, TypeORM, Redis, Kafka,
AWS (S3, EC2, Cognito, DynamoDB).

Key Projects & Impact:

Microservices Architecture: Designed and worked within a microservices architecture
with dedicated services for authorization, third-party integrations, and core business
logic, using Kafka event streaming and Redis Pub/Sub for real-time inter-service
communication.

Enterprise System Integrations: Took full ownership of integrations with 5 major
platforms, including Magento, Shopify, Zendesk, and Salesforce, from reverse-
engineering partner APIs and creating technical schemas to final testing and
deployment.

AI-Assisted Support Routing: Built backend logic for a chat widget supporting
automated request resolution, with fallback routing to expert agents using per-partner
decision trees when self-service resolution wasn't possible.

Performance Optimization: Solved critical API rate-limiting issues by implementing
batch update logic and Redis-based distributed locks, ensuring data consistency during
high-traffic periods.

January 2020 - Junior Front-End Developer
June 2021 SPD-Ukraine
Tech Stack: TypeScript, React, GraphQL, Apollo Client, MaterialUI, Storybook, Postman,
PWA, Jest, React Testing Library, Jira, OAuth, Bitbucket.

Key Projects & Impact:

Financial Dashboard Development: Built the user interface for a family budget and
financial planning tool, focusing on creating clear, interactive dashboards for tracking
expenses and savings.

Complex State Management: Used Redux to handle the application's complex data flow,
ensuring that financial figures, transaction lists, and budget limits stayed synchronized
across different views.

Data Visualization: Implemented charts and progress bars to help users visualize their
spending habits, making it easier for them to understand their financial health at a
glance.

UI Consistency & Performance: Focused on writing modular, reusable React
components to keep the codebase maintainable. Optimized frontend rendering to
ensure the app felt fast and responsive even when loading large amounts of transaction
history.

Internship
November 2019 - Junior Front-End Developer
January 2020 SPD-Ukraine
Tech Stack: TypeScript, React, Redux, MaterialUI, OAuth, Jest.

Key Projects & Impact:

Employee Mood Monitoring Platform: Contributed to the frontend of an internal team
project integrated with the company's existing employee database, supporting custom
survey creation and employee profile management.

Authentication: Implemented OAuth-based authorization to connect the platform with
existing employee identity data.

Education
2019 SPD University - Front-End Development
Program Completed a hands-on front-end training program covering team-based web
application development from scratch to production using a modern front-end stack.
(Certificate obtained)