Alexey Karasev, Functional Programming Developer in Moscow, Russia
Alexey Karasev

Functional Programming Developer in Moscow, Russia

Member since May 4, 2017
Alexey is proficient or more so in at least ten programming languages. He's obsessed with studying different approaches and loves comparing the best ones because he wants to start his own software company one day. During his software career, Alexey was shocked about how many man hours go into bug-fixing and refactoring. Thus he uses best approaches from functional programming and OOP to avoid bugs focus on what really matters—feature delivery.
Alexey is now available for hire




Moscow, Russia



Preferred Environment

Git, Visual Studio Code, Docker, MacOS

The most amazing...

...thing I've created is a full featured e-commerce system backed up by custom payments system including crypto and fiat transactions


  • CTO

    2017 - 2019
    • Created an eCommerce system from scratch using microservices architecture.
    • Built a payments system with cryptocurrency and fiat systems.
    • Created an online testing platform for new hires.
    Technologies: React, Ruby, Rust
  • Senior Full-stack Developer

    2016 - 2018
    Friends and Guests
    • Aided in the deployment of the product to beta release as a front-end (React) and back-end (Ruby on Rails) developer.
    • Led several React, Angular, and Ruby on Rails consulting projects, namely:,,, and more.
    • Developed and led a team for a mobile app (fashion) in React Native.
    • Created a web data scraper in Rust.
    Technologies: Ruby on Rails (RoR), Ruby, React
  • Full-stack Developer

    2017 - 2017
    • Created a new programming language parser in Scala.
    • Built a live D3.js visualization of class diagram, sequence diagram, and connectivity.
    • Updated a back-end that implemented a Git system (analog of GitHub).
    Technologies: React, Scala
  • Microservices Developer

    2017 - 2017
    Orpiva Ltd
    • Developed a stable service for a URL shortening service, which is used internally for user convenience and tracking behavioral metrics.
    • Stabilized an existing Elasticsearch service (i.e., for gracefully handling network partitions of used microservices).
    Technologies: Scala
  • Senior Mobile Developer

    2016 - 2017
    Secret Lab
    • Led a team of two programmers in an iOS app project for the major bank.
    • Developed an Android app for parents where they can view student marks and school schedules.
    Technologies: Android, Objective-C, Swift, iOS
  • Full-stack Developer

    2015 - 2016
    • Sped-up a Ruby on Rails server response time 5-fold.
    • Created a Go server and deployed a Hadoop cluster for a user behavior tracking system.
    • Assisted in the roll-out a new front-end (AngularJS).
    Technologies: Hadoop, Go, Ruby on Rails (RoR), Ruby, AngularJS


  • Storiqa

    The project successfully raised approximately US$25 million in ICO.

    My goal as a CTO was to hire and lead a team to build two big projects from scratch: an eCommerce platform and a cryptocurrency payments system.

    Technologies: Rust, Ruby, React, PostgreSQL, RabbitMQ

  • Everwise

    This is a startup focused on SaaS for talent development. The core task for me and my team was to migrate a huge existing codebase from Angular to React. We successfully completed this task and removed each and every Angular line of code, while maintaining existing features and adding new features with React.

    Technologies: React, Angular, Ruby on Rails


    This is a massive open online course (MOOC) that's mainly focused on JavaScript. I'm helping them migrate from Angular to React and building version 2 of the application.

    Technologies: Angular, React, Redux, Rails

  • Diary

    This is an Android app for tracking the schedules and the grades of school children. I developed this app from scratch.


  • Friends and Guests: Connecting Hosts and Guests™

    Friends and Guests is a niche competitor of Airbnb. For their project, I worked as a full-stack programmer—mainly focused on the development of new features

    Technologies: Ruby on Rails, React, PostgreSQL

  • Wallet

    This is a startup project from the number one Russian bank for storing sensitive document information (IDs, discount cards, bank cards, and more). I was a lead developer on this project.


  • Spylight

    This is a mobile fashion app for browsing different looks for celebrities. I was a lead developer on this project.


    This is a unicorn startup that provides a SaaS for the construction industry. I helped the Procore team to add React components for a module that draws up the floor plans in the app.

    Technologies: React, Redux, Rails.

  • Madrone Software & Analytics, Inc.

    This is a startup that offers SaaS for hedge fund managers. I was responsible for implementing the new features in the front-end and back-end.

    Technologies: React, Flux, Rails

  • Option/Maybe, Either, and Future Monads in JavaScript, Python, Ruby, Swift, and Scala (Publication)
    If you're searching for the holy grail of bug-free code in JavaScript, Python, Ruby, Swift, and/or Scala, look no further! This monad tutorial by Toptal Freelance Functional Programmer Alexey Karasev takes you from category theory to the practical implementations of the Option/Maybe, Either, and Future monads, plus a sample program—in all five languages.


  • Languages

    JavaScript, Scala, Swift, Ruby, Java, Objective-C, Go, Rust
  • Frameworks

    Redux, Ruby on Rails (RoR), AngularJS, Play, Hadoop
  • Libraries/APIs

    React, Http4s
  • Tools

    Construction Audit Tracking System (CATS), AWS ECS, Git
  • Platforms

    Android, Docker, iOS, MacOS, Visual Studio Code
  • Storage

    Redis, PostgreSQL, MongoDB, Cassandra


  • Level III charterholder in Finance
    2008 - 2011
    CFA Institute - USA
  • Master's degree in Economics
    2006 - 2008
    New Economic School - Moscow, Russia
  • Specialist degree in Computer Science
    2002 - 2007
    Moscow State University - Moscow, Russia

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