Vasyl

VASYL ONOPRIIENKO – SOFTWARE ENGINEER
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Telegram: https://t.me/vasil_o

SUMMARY
Full-stack Software Engineer with 9+ years of commercial experience designing,
building and scaling back-end systems and web applications with Node.js and TypeScript. Most recently
developed React Flow, a Built for Shopify workflow automation app, across a Remix/React front end and a
distributed Node.js back end (RabbitMQ, GraphQL, MariaDB, MongoDB, Redis).
Before that, spent nearly four years at EPAM Systems delivering cloud-native microservices on AWS (Lambda,
API Gateway, DynamoDB, SQS, EventBridge) for the China market localization of a global fashion retail brand.
Earlier built back ends from scratch for SaaS, fintech, education and mobile products using NestJS, Express,
MongoDB and Microsoft Azure.
Core strengths: event-driven and microservice architecture, REST and GraphQL API design, third-party
integrations (Shopify Admin API, payments, SMS and email providers), production reliability and code review.
Owns features end to end, from requirements to release, in distributed Scrum teams, and uses AI-assisted
development tools (Cursor, Claude Code) to deliver faster.

WORK EXPERIENCE

Full Stack Engineer, DevIT, https://devit.group/
Period: Feb 2025 – Oct 2026 · Remote
Project: React Flow — https://apps.shopify.com/react-flow
Project Description: React Flow is a Shopify app for visual workflow automation (Built for Shopify). Merchants
build no-code workflows: triggers, conditions, loops, and actions for orders, customers, inventory, tagging,
emails, and external integrations. The product is a multi-service application: a Remix front end and Node.js
services (worker, webhook, schedule, trigger, biller, sandbox) that communicate through RabbitMQ.
Project Roles: Full-stack developer
Responsibilities:
• Designed and launched an action that runs any Shopify Admin GraphQL API mutation from a workflow,
so merchants are not limited to prebuilt actions. Added workflow import, export, and archiving so flows
can be moved between stores and kept organized.
• Extended the platform with more than ten triggers and actions: returns, B2B companies and catalogs,
scheduled runs, file transfer, gift cards, and inventory transfers. Added webhook testing and HMAC
authentication for external integrations.
• Made the workflow engine more reliable: fixed loop execution order, blocked invalid loop nesting, added
event retries, and handled app uninstalls correctly. Upgraded the Liquid template engine with backward
compatibility for existing customer workflows.
• Created a library of about thirty ready-made automation templates for order, customer, and product

tagging, reminders, and payment handling.
• Improved SMTP, Google Sheets, Mailchimp, and Twilio integrations and fixed UX issues. Internal tools
for generating triggers and actions and for converting Figma designs to Shopify Polaris sped up the team.
Tools and Technologies: Remix, React.js, Node.js, TypeScript, GraphQL, Shopify, Shopify Polaris, Koa.js,
RabbitMQ, MariaDB, MongoDB, Redis, Sentry, Liquid, Docker

Software developer, EPAM Systems, https://www.epam.com/
Customer: Company APAC
Customer Description: Retail & Distribution
EPAM Project Description: The goal of the Company APAC Project is to implement Chinese localization and
enhancements of the Company official website, utilizing the expertise of EPAM in software development. Focus
on runway shows, seasonal campaigns, new products and special events to drive brand heat.
The main objectives of the website are Chinese localization of the user experience. Modules are HP/LP, PLP,
PDP, My account, Shopping bag, Recommendation, Checkout.
Website implementation using front-end micro-services, while for back-end we use BFF pattern. Besides
integration with API layer (AWS interconnection).
GitLab CI/CD, best EngX practices in place, multiple QA environments for the simultaneous delivery and
flexibility to release features.
Tech Stack: JavaScript, Typescript, Node.js, AWS Cloud services, Express.js, AWS lambda functions,
DynamoDB and Datastax database, Commerce tools API
During the business aim, I also worked in another team to speed up a feature release. Collaboration with others
team are also a huge part of the success of implementation of the feature.
Project Roles: Key Developer, Cloud Application Support, Cloud Platform Developer, Developer
Responsibilities:
• In a project, I was focused on the China API for the renowned company. My role in this project is
multifaceted, encompassing the creation, updating, and support of micro services;
• To achieve the business objectives, I leverage a range of technologies and languages that include Node.js,
JavaScript, Typescript, and Express.js. I also utilize AWS Cloud services, which provide a robust and
flexible platform for our project needs;
• One of my key responsibilities is the addition of new features to enhance the functionality and user
experience of the API. This involves a thorough understanding of the business requirements, devising
effective solutions, and implementing these features in a way that aligns with the overall project
architecture;
• Furthermore, I am involved in code reviews, a critical process that ensures the quality and maintainability
of our codebase. By examining my teammates' code, I can provide constructive feedback and suggestions
for improvement, fostering a culture of continuous learning and improvement within our team;
Tools and Technologies: Datastax, Amazon DynamoDB, Cucumber JS, Express, ESLint, Node.js, Jest, AWS
Lambda, Amazon S3, AWS CloudFormation, Amazon CloudWatch, AWS API Management, Amazon
EventBridge, Typescript, AWS SQS, Commercetools Platform, Wechat, JavaScript, New Relic, AWS Secrets
Manager, AWS AppConfig, SAP HANA Platform

Pascalium company projects:

Middle Back-end developer, NDA
Customer: USA
Project Description: NDA
Project Roles: Support, update and create new services
Responsibilities:
• As part of my ongoing responsibilities, I am tasked with the support, updating, and creation of new
services. This entails a broad range of activities that collectively aim to enhance the functionality,
efficiency, and overall performance of our projects;
• Supporting existing services is a critical aspect of my role. This involves troubleshooting and resolving
any issues that may arise, whether they are technical glitches, performance bottlenecks, or user-reported
problems. I work diligently to ensure that these services continue to operate smoothly and effectively,
minimizing downtime and disruption to our users.
Tools and Technologies: Amazon DynamoDB, ESLint, Kubernetes, AWS Lambda, Cloud Platforms, Amazon
S3, Node.js, AWS Amplify

Middle Back-end developer, NDA
Customer: NDA
Project Description: SaaS service to connect people by interests or to find mentor or mentee. Comprehensive
management and development of micro services and API endpoints. The project aimed to facilitate connection
and mentorship among users with similar interests. The team adopted a SCRUM-based approach to consistently
discuss project features, architecture, and issues. Utilizing the Nest.js framework, Azure Cosmos DB, and Azure
Service Bus, the team successfully facilitated seamless communication between micro services using robust
messaging infrastructure (topics and queues) ensuring improved system efficiency, resilience, and scalability.
Project Roles: Support, update and create new micro services and API endpoints
Responsibilities:
• I played a role in supporting, creating, and updating micro services. This involved a wide range of
activities, from troubleshooting and resolving issues to implementing updates and developing new
services to meet evolving business needs;
• To facilitate these tasks, I utilized the NestJS framework, a progressive Node.js framework that allows for
the efficient creation of scalable server-side applications. NestJS provided a robust foundation for our
micro service architecture, offering a blend of object-oriented programming, functional programming, and
functional reactive programming.
Tools and Technologies: Azure Cosmos DB, SwaggerHub, Telepresence, Log management tools, Azure Service
Bus, ESLint, Monitoring and log management tools, Sentry, supertest, Jira, Kubernetes, OpenAPI Specification
(OAS), Typescript, AngularJS, Express, JavaScript, Microsoft Azure, Node.js, NestJS

Back-end developer, Kokoro
Customer: Kokoro - Create the right conditions for successful teams
Project Description: Kokoro offers services and software to help teams move and improve. Use our tool to

understand employee experience, hold better meetings and build healthy high performing teams. Key features
included the development of real-time, bidirectional, and event-based notifications using socket.io for iOS and
Android apps. We designed and integrated comprehensive DB schemas and utilized Nexmo SMS and MailGun
services for efficient user communication. The project emphasized real-time user interaction, an efficient back-
end, and seamless database management.
Project Roles: Develop FE and mobile back-end from scratch
Responsibilities:
• I also integrated the Nexmo SMS service into our application, a feature that allowed us to send text
messages to our users. During this process, I encountered and successfully resolved bottleneck issues,
ensuring that our SMS service was able to handle high volumes of messages without compromising
performance;
• Lastly, I implemented a mail service using MailGun, a powerful email service provider. This allowed us
to send, receive, and track emails effortlessly, improving our communication with users.
Tools and Technologies: MongoDB, ESLint, WebSockets, Mail Gateways, SwaggerHub, Express, SMS,
Notifications in iOS, Node.js, Android SDK, OpenAPI Specification (OAS)

Back-end developer, Virtuprofs
Customer: Virtuprofs - educational platform accessible by call
Project Description: Intended for all students from primary to secondary school, the VirtuProfs application
provides you with qualified teachers, thousands of multiple choice questions, course notes, lessons,
documentation and telephone or SMS support 7 days a week. Allows students to realize their full potential by
providing them with an educational platform accessible by call.
Project Roles: Develop mobile back-end from scratch
Responsibilities:
• I had the exciting opportunity to develop a project from scratch, providing me with a blank canvas to
architect, design, and implement a robust and scalable solution;
• One of the significant features I implemented in this project was a payment system. Recognizing the
importance of providing users with multiple payment options, I integrated two popular payment APIs -
Orange Web Payment API and Paypal Payment API.
Tools and Technologies: MongoDB, JetBrains WebStorm, ESLint, Jest, WebSockets, Express, Electronic
Payment, Notifications in iOS, Node.js, Android SDK, OpenAPI Specification (OAS)

Middle Back-end developer, NDA
Customer: NDA, Internal Poll Management
Project Description: NDA
Project Roles: Support, update and create new services
Responsibilities: I was tasked with the development of a back-end server from the ground up. This was a
comprehensive task that involved various aspects of back-end development, requiring both technical proficiency
and a deep understanding of the project's requirements.
Tools and Technologies: MongoDB, WebSockets, Express, SMS, Notifications in iOS, Node.js, Android SDK,
Mongoose, OpenAPI Specification (OAS), TypeScript, JavaScript

Middle Back-end developer, NDA
Customer: NDA, Financial System
Project Description: NDA
Project Roles: Support, update and create new services
Responsibilities: As a back-end developer, I was responsible for creating and maintaining the server-side logic of
the company's applications. Involves designing and implementing efficient algorithms and data structures to
handle financial transactions and data.
Tools and Technologies: MongoDB, JetBrains WebStorm, ESLint, Jest, AngularJS, Express, Node.js, OpenAPI
Specification (OAS)

Middle Back-end developer, Transfer.ck.ua
Customer: Transfer.ck.ua. Internal management system
Project Description: The project involved the development of the back-end infrastructure from scratch to support
the operations of Transfer Cherkasy. This included adjustments to services due to geopolitical changes affecting
routes and operations, enhancing safety and quality of transportation services. The system was designed to
integrate updated car models, safety measures, and bespoke passenger services coordinated with both local and
international travel requirements.
Project Roles: Develop back-end infrastructure
Tools and Technologies: MongoDB, ESLint, New Relic, Jest, TypeScript, WebSockets, JavaScript, Node.js

Middle Back-end developer, Delica, Guardian, Parking App (One Client)
Customer: Delica
Project Description: A parking application serves as a comprehensive solution for managing and streamlining
parking operations, whether it's for a small parking lot or an entire city's parking infrastructure. The application
aims to make parking easier, more efficient, and more convenient for both drivers and parking operators.
Project Roles: Support, update and create new services
Responsibilities:
• I was responsible for supporting, creating, and updating the REST API. This responsibility was crucial as
APIs are the backbone of any application, enabling different software applications to communicate with
each other and exchange data;
• Supporting the REST API involved troubleshooting and resolving any issues that arose, ensuring the
API's smooth operation. This task required a deep understanding of REST principles and a keen eye for
detail to identify and fix any problems quickly.
Tools and Technologies: MongoDB, ESLint, Jest, WebSockets, JavaScript, Node.js

Middle Back-end developer, Papirux 2
Customer: Documentation platform
Project Description: In this pivotal update of an established application, we undertook a comprehensive
reworking of several core functionalities to enhance user experience and system efficiency. Significant
improvements were made to the document versioning and storage capabilities, ensuring more reliable and scalable
management of user data.

Project Roles: Develop back-end infrastructure
Responsibilities:
• I was tasked with integrating a paid subscription feature, an important enhancement aimed at generating
revenue and providing additional value to our users. The chosen platform for this task was Stripe.io, a
leading online payment processing platform known for its flexibility, security, and ease of use.
Tools and Technologies: MongoDB, Node.js API, JavaScript, Stripe

EDUCATION
Name of the Education Establishment: CHERKASY NATIONAL UNIVERSITY NAMED AFTER BOGDAN
KHMELNITSKY
Faculty/College: Computer Science
Department: Computer Sciences
Specialty: Computer ecology-economy monitoring
Degree (diploma): Specialist

TRAINING COURSES
Discipline: MongoDB, Node.js advanced course, etc.