Sergey Petushkou, Developer in Kraków, Poland
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Sergey Petushkou

Verified Expert  in Engineering

Bio

Sergey is a senior full-stack engineer with 10+ years of experience, specializing in JavaScript, Node.js, and React. He has worked with IT startups and large businesses worldwide, including the US and Europe. Collaborating cross-functionally and leading and mentoring teams, he has built distributed, high-throughput, cloud-native applications for handling real-time data. Sergey produces the highest quality work and code, focusing on industry standards in security and performance practices.

Portfolio

IBM
Node.js, React, TypeScript, Microservices, RabbitMQ, gRPC...
Adidas
TypeScript, NestJS, MongoDB, Docker, Kubernetes, Software Development
Lumenalta
Node.js, Express.js, React, Amazon Web Services (AWS), JavaScript, TypeScript...

Experience

  • JavaScript - 10 years
  • Amazon Web Services (AWS) - 10 years
  • Node.js - 10 years
  • Microservices - 10 years
  • MongoDB - 7 years
  • PostgreSQL - 7 years
  • TypeScript - 7 years
  • React - 7 years

Availability

Full-time

Preferred Environment

JavaScript, Amazon Web Services (AWS), TypeScript, React, Microservices, Node.js, Docker, PostgreSQL, MongoDB, Redis

The most amazing...

...thing I've developed is an IBM e-learning app for IBM employees, with over 40,000 users.

Work Experience

Senior Full-stack Software Engineer

2021 - 2025
IBM
  • Led a development team of five for an internal e-learning platform.
  • Designed, developed, and maintained a microservices architecture and API that could scale to tens of thousands of daily users. Implemented horizontal scaling strategies to handle traffic surges.
  • Created and optimized databases for different microservices. Applied seamless database interactions, schema migrations, and efficient query handling and implemented different caching strategies, reducing database load and improving response times.
  • Integrated authentication to secure user sessions and API access. Ensured compliance with corporate security policies.
  • Developed comprehensive unit, integration, and end-to-end tests and conducted load and stress testing to ensure system reliability. Ensured high code quality and stability by integrating code linters and formatters.
  • Participated in creating the user interface using React for a responsive e-learning platform, providing a seamless experience for thousands of IBM employees across regions.
  • Reduced application maintenance costs by optimizing cloud database storage and enhancing the cloud microservices architecture, resulting in performance improvements and long-term cost efficiency.
  • Introduced modular learning pathways. Designed a feature enabling personalized learning pathways based on user preferences and skills, boosting the platform's training completion rate.
  • Implemented an advanced face and desktop video recording tool, enabling hundreds of users and instructors to create video content directly in any modern web browser.
  • Worked in an Agile-Scrum environment, participating in daily standups, sprint planning, and retrospectives. Collaborated with functional teams, integrating APIs, features, and fixes. Engaged with DevOps teams to optimize deployments and monitoring.
Technologies: Node.js, React, TypeScript, Microservices, RabbitMQ, gRPC, Amazon Web Services (AWS), Software Development

Senior Full-stack Software Engineer

2018 - 2021
Adidas
  • Managed a team of five people. Integrated and developed real-time inventory tracking and automated warehouse operations, improving order fulfillment speed by approximately 15% and reducing stock discrepancies.
  • Reduced delivery times by enhancing key software components that optimized supply chain operations, including tracking shipments, automating order routing, and improving supplier coordination.
  • Led a monthly knowledge-sharing session focused on emerging technologies, inspiring junior engineers to adopt innovative solutions. The initiative resulted in three new project proposals from the junior team members.
  • Modernized the unit and integration testing environments.
Technologies: TypeScript, NestJS, MongoDB, Docker, Kubernetes, Software Development

Senior Full-stack Software Engineer

2015 - 2018
Lumenalta
  • Provided development and consulting services to five international clients: Enovos.lu (Luxembourg), a talent recruiting company in Lithuania, TradeZing.com (USA), LingSoft.fi (Finland), and SteelTrace.co (Netherlands).
  • Collaborated with cross-functional teams to build two large-scale applications from scratch, developed one MVP-ready application, modernized three internal applications, and processed ongoing support for a single SaaS service.
  • Reduced development time and costs on projects, saving hundreds of man-hours and tens of thousands of dollars.
Technologies: Node.js, Express.js, React, Amazon Web Services (AWS), JavaScript, TypeScript, Software Development

Senior Full-stack Software Engineer

2015 - 2017
Clevertech
  • Provided development and consulting services to five international clients, such as Enovos.lu (Luxembourg), JayDevs.com (Lithuania), TradeZing.com (USA), LingSoft.fi (Finland), Steeltrace.co (Netherlands).
  • Collaborated with cross-functional teams to build two large-scale applications from scratch, developed one MVP-ready application, modernized three internal applications, and processed ongoing support for a single SaaS service.
  • Reduced development time and costs on projects, saving hundreds of man-hours and tens of thousands of dollars.
Technologies: Node.js

Software Engineer

2010 - 2015
Zynga
  • Developed high-performance game back-end services. Built scalable back-end services to handle thousands of concurrent players across games, ensuring seamless gameplay and reliable server performance.
  • Optimized game data storage. Worked on database optimization for player profiles, game states, and transactions, improving data retrieval speeds and reducing server load.
  • Removed or upgraded outdated dependencies in over 11 microservices. Integrated either self-written code or similar 3rd-party libraries.
Technologies: Node.js

Experience

IBM Stand and Deliver

An internal e-learning application developed for IBM employees.

As a senior full-stack developer, I worked on building a microservices-based architecture for the app, which supported around 40,000 users. The application enabled users to upload and manage their video recordings with complex internal content approval workflows, which was central in delivering training content. It also integrated IBM Watson AI for analyzing, transcribing, and censoring video files.

Additionally, the app featured AWS integration for real-time functionalities, reporting, and dashboards to monitor progress and performance.

Education

2005 - 2010

Bachelor's Degree in Mathematics and Computer Science

Belarusian State University - Minsk, Belarus

Skills

Libraries/APIs

React, Node.js, REST APIs, OpenID, Socket.IO

Tools

RabbitMQ, Git, Terraform

Languages

JavaScript, TypeScript, SQL, GraphQL

Frameworks

NestJS, Express.js, Swagger, Jest, gRPC, Next.js

Paradigms

Microservices, Object-oriented Programming (OOP), Database Design, Design Patterns

Platforms

Amazon Web Services (AWS), Docker, Kubernetes, Apache Kafka

Storage

MongoDB, PostgreSQL, Redis, Elasticsearch

Other

Software Development, SOLID Principles, GitFlow, OAuth, System Design, CI/CD Pipelines, GitHub Actions

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