Sergey Moiseev, Full-stack Developer in Tallinn, Estonia
Sergey Moiseev

Full-stack Developer in Tallinn, Estonia

Member since March 23, 2014
Sergey is a full-stack software engineer with experience developing complex web projects. He has extensive skills as an analyst and with gathering requirements for project development. He boasts practical experience in all levels of participation from full-stack developer to team lead/CTO. He is a top 5% answerer for AngularJS on StackOverflow, and top 10% on Ruby on Rails.
Sergey is now available for hire




Tallinn, Estonia



Preferred Environment

Ruby, Rails, Angular

The most amazing...

...things I've done are migrations for projects of different kinds to newer frameworks and architectures, making them respond to business needs faster.


  • Full-stack Developer

    2018 - PRESENT
    Ygrene Energy Fund (via Toptal)
    • Helped create new prequalification/application process applications with Angular 6 and NgRx.
    • Helped create a monorepo layout for Angular apps using NX, NGRX, shared modules, and environment to deliver new front-end projects quickly and efficiently.
    • Created a supporting proxy-like module for a new application process back end to provide new workflows in an existing feature-flag based process without additional data models using Rails.
    • Supported an automated underwriting system implementation by covering all key Ruby code to make it reliable and maintainable.
    • Implemented the initial message bus encryption mechanism for securing microservice interoperation (Ruby, AWS SQS).
    • Migrated multiple services from Scala to Ruby using Scala code as a source of requirements. Services include external postal providers, environment management solutions (backup scrubbing, event-based S3 archival solution), GIS based solutions, and area configuration service.
    • Helped maintain and improve automatic microservice client generation using the zero-rails_openapi gem and openapi-generator.
    Technologies: Angular 6-9, Ruby on Rails, AWS, Kubernetes, Scala, Docker, Swagger
  • Full-stack Web Developer

    2017 - 2018
    Caspar Health (via Toptal)
    • Created a front-end application for the main business platform utilizing Angular 5 and Ngrx.
    • Helped release a product that made one of five finalists at Disrupt Berlin Startup Battlefield 2017.
    • Helped refactor and develop the back end of a Ruby on Rails application.
    Technologies: Angular 5, Ngrx, Ruby on Rails 5, PostgreSQL, Docker, AWS
  • Full-stack Web Developer

    2017 - 2017
    Everwill (via Toptal)
    • Set up and moved an AWS Elastic Beanstalk Multicontainer Docker configuration to production.
    • Built a new version of the company's main application on Angular 4.
    • Implemented a flexible workflow engine for the application.
    Technologies: Angular 4, Ngrx, Ruby on Rails, MongoDB, Docker, AWS Elastic Beanstalk
  • Full-stack Web Developer

    2014 - 2017
    International Technological University (via Toptal)
    • Implemented ITU Bridge (a project to help students and alumni to apply for jobs at top companies).
    • Implemented ITU's own single sign-on solution, ITU ID.
    • Implemented ITU Student Relationship Management, a system for automation of data and documents collection process for admissions. The system included Stripe and SalesForce integrations.
    • Worked as a back-end Rails developer as well as an AngularJS front-end developer and DevOps for all mentioned projects.
    Technologies: Ruby on Rails, AngularJS, HTML5, CSS3, Redux, MySQL
  • CTO

    2013 - 2014
    Information Ideas
    • Implemented a production-ready SPA job search site.
    • Formed a team of two developers to work on a project.
    • Built a set of AngularJS directives for competence tree rendering and selection.
    • Created a competence search engine on top of Redis.
    • Created a complex UI with interacting controls on top of AngularJS.
    Technologies: Ruby on Rails, PostgreSQL, Redis, AngularJS
  • Development Team Lead

    2012 - 2013
    HeadHunter Group
    • Implemented an online competence-based candidate search project in a small team of three developers.
    • Provided a full cycle of requirements analysis for the project.
    • Implemented property search on top of a Redis set intersection.
    • Built a RIA interface for a project using Backbone.js.
    • Created an automated competence pre-fill solution using candidate resumes as the data source.
    Technologies: Ruby on Rails, PostgreSQL, Redis, Backbone.js
  • CTO

    2011 - 2012
    KupiKupon Global
    • Supported a high-load production environment for a daily deal site on top of Drupal.
    • Managed and implemented a new version of a site using Ruby on Rails.
    • Migrated all data to a new project and replaced the old project with the new one.
    • Formed a development team of ten developers.
    • Implemented a VoIP call center solution based on Asterisk PBX.
    Technologies: Ruby on Rails, PostgreSQL
  • CTO

    2008 - 2011
    Digital Distribution Center
    • Formed a team and started an internal software development process in the company.
    • Moved an outsourced project with the support of a formed team and completed its development from early prototype to production ready version.
    • Managed a complete rewrite of the project from PHP to Ruby on Rails.
    • Created an in-house DRM for the project.
    • Applied Agile practices to the working process and set up a development cycle for the company.
    Technologies: Ruby on Rails, PostgreSQL, PHP, Flash, Flex, VMWare
  • Lead Developer, System Analyst, Head of R&D

    2004 - 2008
    Chronopay B.V.
    • Implemented integrations with Parex (, UCS (, and other payment providers.
    • Developed many improvements to the Chronopay PSP system. Included many new architectural improvements, integration processing, 3D secure implementation, etc.
    • Applied Agile practices in the working process and set up the development cycle for the company.
    • Provided analytical support for the work cycle of the R&D department. Provided a full cycle of business analysis for the company.
    • Managed a development team (five developers).
    • Provided support for three annual PCI DSS certifications.
    Technologies: PHP, PostgreSQL, Mono
  • Lead SW Developer

    2000 - 2001
    • Developed (currently unavailable) from base technical requirements to product in use.
    • Managed a team of three developers in the process of developing
    • Developed modules for the Ayaxi main product ­Ayaxi Publisher, used in client installations.
    • Provided development analysis for the early stages of the President of Russia's website [].
    • Developed methods for outsourcing work support, code format requirements, and documentation format guides.
    Technologies: ASP, MS SQL


  • - Russian E-library (Development)

    I managed this project and wrote a large amount of its code.

  • Everwill (Development)

    Everwill Online Wizard experience was implemented using Angular 4 and Twitter Bootstrap 4. It's a responsive mobile first application with rich user interface.

  • An Angular 5 Tutorial: Step by Step Guide to Your First Angular 5 App (Publication)
    Angular 5 is a new version of the Angular framework developed by Google. Angular 5 comes with improvements including optimized builds and faster compile times, but in this Angular 5 tutorial, we are going to build a notes app from scratch. If you’ve been waiting to learn Angular 5, this tutorial is for you.


  • Languages

    Ruby, UML, Sass, CSS3, Haml, CoffeeScript, HTML5, JavaScript, SQL-99
  • Frameworks

    Angular, Ruby on Rails (RoR), AngularJS, Angular Material, Slim, Factory Girl, Bootstrap, Swagger, Protractor, Redux
  • Libraries/APIs

    Devise, ngrx, Pundit, Stripe API, API, Sidekiq, AngularUI, jQuery, Restangular, Backbone.js
  • Platforms

    Docker, Linux, MacOS, Windows, Kubernetes
  • Storage

    PostgreSQL, MySQL, Redis, MongoDB
  • Other

    State Machines, RESTful APIs, RESTful Web Services, Puma, ISO 8583
  • Tools

    Nginx, Git, RSpec, Git Flow, Capistrano


  • Master's degree in Computer Engineering
    1995 - 2001
    Moscow State Institute of Electronics and Mathematics (Technical University) - Moscow, Russia

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