Sergei Grigorchuk, Full-stack Developer in Saint Petersburg, Russia
Sergei Grigorchuk

Full-stack Developer in Saint Petersburg, Russia

Member since January 25, 2016
Sergey is an experienced software developer. He has worked for IT companies from the US and the UK as a full-stack developer. He loves his job and always looks forward to helping his clients at Toptal to create amazing things.
Sergei is now available for hire



  • Java, 15 years
  • Full-stack, 5 years
  • JavaScript, 5 years
  • jQuery, 5 years
  • Spring Boot, 2 years
  • PostgreSQL, 2 years
  • AngularJS, 2 years


Saint Petersburg, Russia



Preferred Environment

Java, Spring Boot, Git, IDEA, Eclipse IDE, Angular

The most amazing...

...thing I've coded is a business application that is used by thousands of people every day in their job.


  • Architect, Team Lead

    2018 - 2019
    EarthlinkTele (via Toptal)
    • Designed and developed a high-load microservice back end for a social network.
    • Integrated more than 10 different microservices with Spring Cloud.
    • Improved the performance of PostgreSQL by caching data in Elasticsearch.
    • Integrated the back end with Redis for caching response of high-load endpoints.
    • Integrated the back end with an existing OAuth service (IdentityServer) and S3 service.
    Technologies: Java, Spring Boot, PostgreSQL, ElasticSearch, Kafka, Redis
  • Senior Java Developer, Architect

    2017 - 2018
    • Designed a service based on big data and machine learning for identifying categories of construction materials.
    • Designed and developed a neural analysis service of documents that extracts data from typical (DOCx, XLSx, PDF, PNG...) files.
    • Designed architecture for the system (DB, load balancing, chat subsystem, Telegram integration).
    Technologies: Java, Play Framework, Spring Boot, PostgreSQL, AngularJS
  • Senior Java Developer

    2016 - 2017
    Imandra (via Toptal)
    • Designed ad developed Spring Boot-based microservices for authentication, data store, analysis, etc.
    • Simplified the architecture of the app using npm modules instead of creating custom Imandra Modules like the company did previously.
    • Used Docker-Kubernetes to deploy the app.
    Technologies: Spring Boot, MySQL, Angular, Docker
  • Senior Java Developer

    2011 - 2015
    • Designed and developed a business application that helps construction companies control procurement processes.
    • Created web chat based on web sockets.
    • Created image definition to find the best price offer. It's based on FineReader OCR.
    • Designed and created a huge DB for construction materials and equipment.
    • Deployed the application to MS Azure Cloud (load balancing, backup, server-on-demand).
    Technologies: Java, Play Framework, AngularJS, Ractive.js, jQuery, PostgreSQL, MySQL, Twitter Bootstrap, Ajax, REST
  • Senior Java Developer

    2008 - 2010
    CMS Forex (Visual Trading Systems)
    • Designed and developed Forex Web Trader, an application on GWT.
    • Organized continuous integration processes (JIRA + Bamboo + SVN + Maven).
    • Designed a monitoring system for Forex trading that collected metrics and logs from servers.
    • Initiated a migration from Oracle to PostgreSQL.
    • Helped design a DB check control engine that helped to find problems in data.
    Technologies: Java, EJB, Tomcat, JBoss, GWT, Oracle, Hibernate
  • Co-founder, Architect, Senior Java Developer

    2004 - 2007
    • Designed and developed Lemo COBOL IDE, an IDE for COBOL developers that helps to edit sources, compile, and debug programs. The project was sold to Microfocus.
    • Created a JS editor and debugger (based on Eclipse) for Sapience 360.
    • Developed server-side functionality in Java for Ingenico that produces a payment terminal for VISA, MasterCard, etc.
    • Developed a model-driven-architecture engine for accounting software.
    • Designed and developed a web-based math document system for students (Online Mathcad light).
    Technologies: Eclipse, Eclipse RCP, Java, COBOL, JavaScript
  • Java Developer

    2003 - 2004
    • Implemented a data mining algorithms for a big data analysis system.
    • Implemented very fast text search modules based on DFA.
    • Developed Eclipse UI plugins.
    • Integrated Eclipse plugins and a web-based configuration platform.
    • Designed a DB for fast text search.
    Technologies: Java, Eclipse, Tomcat, Servlets


  • Microfocus Visual COBOL for Eclipse (Development)

    In 2004, I founded the startup Lemosoft, which developed Lemo COBOL IDE. In 2007, Microfocus bought Lemo COBOL IDE and founded Microfocus Visual COBOL for Eclipse. I worked for Microfocus as an expert in London for 6 months, passing on my experience.

  • Procurement Chain Software for Construction Companies (Development)

    A trading platform that helps construction companies to find best offers. It collects orders from constructors, organizes tenders, and controls payments and deliveries.

  • Cynteka Pivot Table (Development)

    Cynteka Pivot Table is a jQuery plugin for websites. It supports all the usual pivot table features: data rotating, dragging and dropping fields, summarization, etc.

  • WebTrader for Forex CMS Trading Platform (Development)

    I developed WebTrader- online client for Forex traders. In addition to classic VT-Trader WebTrader allowed traders to perform operations without the need to install a Windows application.

    I used JS, Ext.js, jQuery, Ajax, Long Polling, and GWT. It worked very fast and stable.

  • Entertainment Fun Videos (Development)

    This my own small project. I created this web application that collects small fun videos from YouTube and allows users to merge some videos into a single video. It is used by people to congratulate friends, to create fun videos with politicians, and so on.

    Here's a "Happy birthday" example video for a Russian girl, Julia.

    I used Java, Play, MySQL, Ractive, Bootstrap, and Linux video utilities.


  • Languages

    SQL, Java, HTML, JavaScript, GraphQL, HTML5, Scala, CSS3
  • Frameworks

    Play, AngularJS, Hibernate ORM, Bootstrap 3, Spring JDBC, Hibernate, Spring Security, Spring Boot, JPA, Selenium, Mockito, Akka
  • Storage

    MySQL, PostgreSQL, Spring Data REST, Spring Data, ClickHouse, Memcached, Elasticsearch
  • Libraries/APIs

    jQuery, Ebean ORM, Vue.js 2, Ractive.js, React, Auth0 API, Node.js, jQuery UI, Stomp.js
  • Tools

    Servlet, Maven, Gradle, Docker Compose, Bower, Eclipse IDE, Eclipse RCP, Apache Tomcat, Apache ZooKeeper, Eureka
  • Paradigms

    REST, Microservices, STOMP, High-speed Design
  • Platforms

    Linux, Telegram Bot Platform, Kubernetes, Docker, Azure, Amazon Web Services (AWS), Apache Kafka
  • Other

    Telegram Bots, TextSearch, Math, Full-stack, Ajax, HTTP, Classification Algorithms, Learning, Object Detection, Facial Recognition, Machine Vision, Computer Vision, Boot, Text Processing, SVG, OCR, Apache Commons, WebSockets, High-load, High Availability, Spring Cloud


  • Master of Science degree in Applied Math
    1996 - 2002
    State Electrotechnical University (LETI) - Saint-Petersburg

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