Sergey Kuleshov, MERN Stack Developer in Limassol, Cyprus
Sergey Kuleshov

MERN Stack Developer in Limassol, Cyprus

Member since June 8, 2016
Sergey is a full-stack and cloud web developer with a master's degree in the field of science and over ten years of experience in the industry. With an in-depth knowledge of web technologies, he specializes in Node.js, particularly the MERN stack and DevOps, and he has in-depth experience with the AWS cloud. Sergey has substantial practical experience in iOS development.
Sergey is now available for hire


  • Klartech
    JavaScript, TypeScript, Node.js, Amazon Web Services (AWS)
  • BDswiss
    ReactiveX, React Native, GraphQL, React, Node.js, Android, iOS, Swift, Cloud...
  • SclaeFactor
    Ember.js, Ruby on Rails (RoR), Ruby



Limassol, Cyprus



Preferred Environment

Git, Xcode, Visual Studio Code, Linux, MacOS

The most amazing...

...project I've worked on was a scalable, high-load Forex trading API layer based on microservice architecture.


  • Cloud Architect

    2022 - PRESENT
    • Developed a CD pipeline based on GitHub workflows with deployment to AWS ECS cluster.
    • Designed CI test suite for end-to-end tests of Kafka-based microservices.
    • Developed a NestJS module for validating Kafka messages against Glue JSON schemas.
    Technologies: JavaScript, TypeScript, Node.js, Amazon Web Services (AWS)
  • Team Lead and CIO

    2016 - 2022
    • Designed and implemented high-performance APIs for MetaTrader 4 (MT4) platform based on a Node.js and C++ stack with a RabbitMQ message backbone.
    • Migrated microservices to the AWS Cloud Development Kit based on infrastructure as code best practices.
    • Led the development of a native mobile trading application for iOS and Android.
    • Developed a React and Redux back-office and client portal application.
    Technologies: ReactiveX, React Native, GraphQL, React, Node.js, Android, iOS, Swift, Cloud, UIKit, Amazon Web Services (AWS)
  • Senior Sofware Developer

    2016 - 2016
    • Created a microservice back-end in Ruby on Rails with an EmberJS front end.
    • Worked with the project manager to define the software requirements.
    • Set up a hybrid deployment process with AWS and Digital Ocean.
    Technologies: Ember.js, Ruby on Rails (RoR), Ruby
  • Software Developer

    2013 - 2016
    • Developed an end-to-end testing stack with Cucumber.
    • Implemented new features in a Perl-based fixed income trading back end.
    • Implemented statistics calculations and reporting for fixed income trading exchange.
    • Improved .NET and WinForms based on the client software for individual clients' needs.
    Technologies: Cucumber, Ruby, .NET, C#, Perl
  • CTO

    2012 - 2016
    • Designed and architected secure email communication solutions for iOS, Windows, and other platforms.
    • Developed a native email client for iOS supporting IMAP protocol for all popular email services.
    • Optimized Core Data for large data sets for the best user experience.
    • Implemented compatibility layer for Symantec PGP Universal Server.
    Technologies: Core Data, Cocoa, Objective-C, RubyMotion, iOS
  • CTO

    2011 - 2013
    EXA Solutions
    • Implemented an in-house data management system as a set of Rails engines backed by MongoDB.
    • Built several iOS applications with Objective-C, Core Data, and RestKit.
    • Created a multidimensional statistics system as a Ruby on Rails and a Chrome application backed by a local store.
    • Developed many eCommerce solutions integrating with PayPal and other payment gateways.
    Technologies: Objective-C, MongoDB, Ruby on Rails (RoR), Ruby, PHP
  • Research Analyst

    2008 - 2011
    • Participated in designing and executing field trials of P2P traffic optimization algorithms based on economic incentives under the EU research project SmoothIT.
    • Designed and implemented an internet protocol television (IPTV) eCommerce application.
    • Adapted and completed the quality assurance of the IPTV applications for older people under the EU research project T-Seniority.
    • Implemented video on demand (VOD) and Livestream recording for usage by clients on IPTV platforms.
    • Took part in several research projects and submitted a few proposals.
    Technologies: Networking, Core, P2P, IPTV, JavaScript, Ruby on Rails (RoR), Ruby
  • Software Developer

    2005 - 2007
    • Adapted SugarCRM for the needs of the business selling internet service provider (ISP) services.
    • Developed a phone number catalog for a local call center.
    • Implemented onboard registration for new customers.
    Technologies: .NET, PHP


  • iOS Forex Trading App

    As the team lead and lead iOS developer, I took the most active role in developing the trading application from the ground up, including architecture, high-load server-side APIs, and many UI/UX decisions.

  • DokuCMS

    Open-source CMS and e-shop based on the MERN stack. As a freelance developer, I face specific requirements to regularly develop small, low-budget sites. I needed a tool that would allow me to do it quickly and efficiently; hence, I decided to implement a custom solution and never looked back at any other commercial CMS.

  • Krypto Mail

    Krypto Mail is a full-featured native iOS email app with integrated pretty good privacy (PGP) security, compatible with Symantec PGP, including encryption and digital signatures. Support for all IMAP/SMTP email servers. Integrated with PGP Universal Server.

  • EventSlice

    One stop for all event needs—find and book locations for the event, find professionals, get quotes, and hire the best ones. Manage your budget and much more.


  • Languages

    ECMAScript (ES6), CSS, JavaScript, Swift 5, Kotlin, Ruby, Objective-C, SQL, TypeScript, TypeScript 2, TypeScript 3, PHP, Swift, GraphQL, Perl, C#
  • Frameworks

    Cocoa, Rx, UIKit, React Native, Core Data, Ruby on Rails (RoR), RubyMotion, Redux, Ember.js, .NET
  • Libraries/APIs

    Node.js, React, RxJava 2, RxSwift, Socket.IO, ReactiveX
  • Tools

    Git, RabbitMQ, Xcode, Cucumber
  • Platforms

    Heroku, iOS, Linux, Android, MetaTrader 4, Amazon Web Services (AWS), MacOS, Visual Studio Code
  • Paradigms

    Test-driven Development (TDD)
  • Storage

    Redis, MySQL, Amazon S3 (AWS S3), MongoDB, PostgreSQL
  • Other

    MERN Stack, IPTV, P2P, Networking, Encryption, OpenPGP, Cloud


  • M.Sc. Degree in Computer Science
    2007 - 2008
    Royal Holloway, University of London - Surrey, UK
  • B.Sc. Degree in Mathematics, Computing, and Statistics
    2002 - 2006
    University of London - London, Distance Learning
  • B.Sc. Degree in Computer Science
    2002 - 2005
    Cyprus College - Nicosia, Cyprus

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