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Sergey Kuleshov
Verified Expert in Engineering
MERN Stack Developer
Limassol, Cyprus
Toptal member since June 8, 2016
Bio
Sergey is a full-stack and cloud web developer with a master's degree in the field of science and over 10 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 extensive experience with the AWS cloud. Sergey has substantial practical experience in iOS development.
Portfolio
Klartech
JavaScript, TypeScript, Node.js, Amazon Web Services (AWS), Web Development...
BDswiss
ReactiveX, React Native, GraphQL, React, Node.js, Android, iOS, Swift, Cloud...
SclaeFactor
Ember.js, Ruby on Rails (RoR), Ruby, Web Development
Experience
- TypeScript - 5 years
- Node.js - 3 years
- MERN Stack - 3 years
- React - 3 years
- Amazon - 3 years
Work Experience
Cloud Architect
2022 - PRESENT
Klartech
- Designed and implemented migration to cloud-first architecture leveraging Amazon ECS and AWS Lambda.
- Developed a CD pipeline based on GitHub workflows with deployment to an Amazon ECS cluster.
- Developed a NestJS module to validate Kafka messages against Glue JSON schemas.
- Assumed an active role in migrating multiple services under an Nx-based monorepo with the common stack based on NestJS.
Technologies: JavaScript, TypeScript, Node.js, Amazon Web Services (AWS), Web Development, Docker, DevOps, GraphQL, PostgreSQL, AWS Lambda, Amazon
Team Lead and CIO
2016 - 2022
BDswiss
- Designed and implemented high-performance APIs for the 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 (CDK) based on IaC 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.
- Led the team implementing the company's trading application in React Native.
Technologies: ReactiveX, React Native, GraphQL, React, Node.js, Android, iOS, Swift, Cloud, UIKit, Amazon Web Services (AWS), Full-stack, CSS, Web Development, User Interface (UI), User Experience (UX), Responsive Web Design (RWD), MySQL, Docker, Project Management, DevOps, RxJS, PostgreSQL, AWS Lambda, Amazon
Senior Sofware Developer
2016 - 2016
SclaeFactor
- 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, Web Development
Software Developer
2013 - 2016
Liquidnet
- 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
Douosvavvm
- 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, User Experience (UX)
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, Web Development, MySQL, Stripe API
Research Analyst
2008 - 2011
PrimeTel
- 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, P2P, IPTV, JavaScript, Ruby on Rails (RoR), Ruby, MySQL
Software Developer
2005 - 2007
PrimeTel
- 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
Experience
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
https://github.com/svyatogor/DokuCMSOpen-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.
NDA Project
A crypto investment platform where clients can purchase ERC-20 tokens and stake them into various investment schemes. Staking and profit logic were implemented as smart contracts backed by off-chain oracles.
Education
2007 - 2008
M.Sc. Degree in Computer Science
Royal Holloway, University of London - Surrey, UK
2002 - 2006
B.Sc. Degree in Mathematics, Computing, and Statistics
University of London - London, Distance Learning
2002 - 2005
B.Sc. Degree in Computer Science
Cyprus College - Nicosia, Cyprus
Skills
Libraries/APIs
Node.js, React, RxJS, RxJava 2, RxSwift, Socket.IO, Stripe API, ReactiveX, Stripe
Tools
Git, RabbitMQ, Xcode, Cucumber
Languages
ECMAScript (ES6), CSS, JavaScript, Swift 5, Kotlin, GraphQL, Ruby, Objective-C, SQL, TypeScript, TypeScript 2, TypeScript 3, PHP, Swift, Perl, C#, Solidity
Frameworks
Cocoa, Rx, UIKit, React Native, Core Data, Ruby on Rails (RoR), RubyMotion, Redux, Ember.js, .NET, NestJS, Next.js, Tailwind CSS
Platforms
Heroku, iOS, Linux, Android, MetaTrader 4, Amazon Web Services (AWS), Docker, AWS Lambda, Amazon, MacOS, Visual Studio Code (VS Code), Blockchain
Paradigms
Test-driven Development (TDD), Responsive Web Design (RWD), DevOps
Storage
Redis, PostgreSQL, MySQL, Amazon S3 (AWS S3), MongoDB
Industry Expertise
Project Management
Other
Full-stack, Web Development, MERN Stack, User Experience (UX), IPTV, P2P, Networking, Encryption, OpenPGP, Cloud, User Interface (UI), Team Leadership, Smart Contracts
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