Image of Konstantin 

Konstantin 

  • Java
  • Node.js
  • React

Konstantin is a senior full-stack developer​​ with​​ over 5 years of experience​​ in​​ backend​​ and ​​frontend development.

Konstantin  and more developers are now available for hire.

Hire Konstantin 

Skills and Qualifications

Languages

  • Java
  • JavaScript
  • HTML
  • CSS

Frameworks

  • Spring Core
  • Spring Data JPA
  • Spring Security
  • Spring Boot
  • Spring MVC
  • Hibernate
  • ReactJS
  • Express.js

Libraries/APIs

  • jQuery
  • Redux
  • REST API

Tools

  • JUnit
  • Maven
  • Jenkins
  • Jira
  • GIT
  • Gerrit
  • SVN
  • npm
  • IntelliJ Idea

Platforms

  • Node.js
  • Ethereum

Other

  • Drools
  • RabbitMQ
  • WebSocket
  • Android SDK
  • Solidity
  • Smart Contracts

Data bases

  • MySQL
  • MySQL Workbench

Projects

CRM Integrations

Full-stack Developer

This is an application that integrates IP telephony based on Kazoo with various CRM platforms (and not only CRM ones): Zoho Products, Salesforce CRM, Hubspot CRM, Zendesk, Slack, Zapier. For this purpose, the team implemented a middleware server based on Node.js. Konstantin developed a system for balancing and logging applications and implemented playback of call records, all while ensuring data security. He also developed the UI and a system for managing integration settings for CRM users as well as adding or removing access to the integration. The CI/CD processes were supported by Konstantin. The project was built with Jenkins and its deployment with SaltStack. Test and production server monitoring was implemented via Prometheus and Grafana.


  • Node.JS
  • JavaScript
  • Websocket
  • AES
  • Express.js
  • Monster UI

Frontend Development of Online Translation Management System

JavaScript Developer

This project involved a Translation web application that allows the automation of business processes for translation agencies. Building the app with React allowed the team to get a convenient, responsive, and dynamic changing interface. The team used Redux to store the data in a single repository, which allowed for an instant display of newly loaded components. Konstantin took part in the development of an administrator account and custom wrappers for reducing redux pattern code. He also processed root containers and implemented the modular structure of the components.


  • JavaScript ES6
  • React
  • Redux
  • HTML
  • CSS3
  • WebSocket
  • gRPC
  • npm
  • WebPack
  • Slack
  • Trello
  • Drone.io
  • GitHub
  • Sentry

Management System for Localization Projects

JavaScript Developer

This project involved a corporate web application for managing localization projects. Konstantin took part in the development of the interface based on a spreadsheet interface which included powerful capabilities for user interaction. He implemented several new functions. He was also engaged in improving and refactoring the existing code.


  • HTML
  • CSS3
  • SASS
  • ReactJS
  • Redux
  • JS ES6

IoT Platform

Java Developer

This is an IoT system that exchanges data between the system and external client applications. The system allows for remote reception of information about the status of devices as well as the ability to send control commands and parameter settings, etc. It also allows users to obtain information on consumed resources at scheduled times, or on request from external programs. Konstantin took part in the development and testing of message protocol converters between server-side and target devices.


  • Java8
  • Maven
  • JUnit
  • Git
  • Kaitai
  • Lombok

Creating the Extended Game Mechanics for the Client Role-playing Game

Java Developer

This application is a game based on the rules of the well-known game Dungeons and Dragons. Konstantin performed the following work on the game engine: Development of the new functionality; Expansion of the model; Bug fixing. The UI was developed with Swing and JavaFX technologies since players need a user-friendly and easy-to-use interface for interacting with the game.


  • Java 8
  • Swing
  • JavaFX
  • GIT
  • Jira
  • JUnit
  • Maven
  • Intellij Idea.

Blockchain Research and Development Web Application Using Smart Contracts

Full Stack Developer

Konstantin developed this automated system for decentralized data storage and smart contract execution. He researched and considered different methods of smart contract implementation before implementing the most suitable one for the resources available.


  • Ethereum
  • Smart Contract
  • Truffle
  • Solidity
  • Metamask
  • Solidity
  • Web3.js
  • Angular

A Platform for Attracting Users to Events

Java Developer

The platform he was asked to work on collects statistics of visits to various kinds of events and their responsiveness to various methods of notification (SMS, phone, VK) before ranking users by interests. During the project, Konstantin took part in designing the architecture, the backend development, the creation and implementation of layers, and writing the Unit tests.


  • Java 8
  • RabbitMQ
  • MySQL
  • Spring Core
  • Spring Data JPA
  • Spring Security
  • Spring Boot
  • Spring MVC
  • REST API
  • JUnit
  • Mockito
  • IntelliJ IDEA
  • Maven
  • Jenkins
  • JavaMail API

Learning Platform

Java Developer

A web app for a learning platform. For this project, Konstantin implemented the following features: Course designer (e.g. an opportunity to create a course) Choosing and passing the courses Module for convenient planning of studying. He used Angular for the frontend side and Spring for backend. The connection was implemented using Rest API.


  • Java 7
  • Spring Core
  • Spring Data JPA
  • Spring Security
  • Spring Boot
  • Spring MVC
  • JWT
  • REST API
  • JUnit; TypeScript
  • Angular
  • Angular Material
  • Materialize
  • Angular CLI.

Mail-client for Android

Java Developer

This was an Android mail client mobile application. Konstantin solved the existing problems relating to users working with emails. He also designed interfaces that adhered precisely to the material design.


  • Java 7
  • Android SDK
  • JavaMail
  • Android Studio