Валерий

Valerii Manchenko
Full Stack Developer
 Ukraine, Kharkiv  [відкрити контакти](див. вище в блоці «контактна інформація»)  [відкрити контакти](див. вище в блоці «контактна інформація»)

Summary
Dynamic Full Stack Developer with 11+ years of experience in React, Node.js, and Solidity. Skilled in building scalable
backend services, intuitive user interfaces, and complex system integrations. Strong expertise in RESTful APIs,
microservices, database architecture, and automated testing. Focused on performance, reliability, and delivering high-
quality software in fast-paced environments.

End-to-end development: from architecture to production

Node.js, React, PHP, Solidity, async/await
REST APIs, microservices, relational & NoSQL databases

Third-party API integrations

Clean code, automated tests, performance optimization
Fast learner with excellent task and time management

Experience
Ensuria 2025
Full Stack Developer
Developed and maintained backend services using Node.js, NestJS, TypeScript and microservice architecture.

Worked with React, Next.js, Redux and Mantine UI, including integrating Mantine as a UI library and implementing
internal interface components.
Built internal CRM modules and automated business logic for claims, conversations, notifications, and user
management.
Integrated multiple third-party APIs, including Zendesk, messaging platforms, payment providers, and internal service
APIs.
Designed and optimized RESTful APIs, ensuring high performance, scalability, and reliability.

Participated in architecture planning, refactored legacy modules, and improved overall system stability.

Improved performance of high-load endpoints, optimized SQL queries, and reduced response times.
Worked with PostgreSQL, Sequelize, Redis, caching strategies, transactions, and migrations.

Utilized Git, code review practices, documentation writing
Wrote automated tests (unit, integration, e2e) to ensure code quality, reliability, and regression prevention.

MegaDev, nChain, Coinsender, etc. Feb 2023 – 2025
Full Stack Developer

Developed end-to-end Web3 solutions from Solidity smart contracts to full front-end and back-end implementations.
Built decentralized applications (dApps) using Solidity, including ERC-20, ERC-721, staking logic, and custom
contract architectures.

Developed web platforms using React and Next.js and mobile applications using React Native, including integrations
with blockchain services.

Implemented global state management with Redux, Reselect, and redux-form, optimizing front-end performance.
Built and optimized backend services using Node.js and TypeScript, including RESTful APIs and authentication
systems.

Integrated Web3/Ethers.js with smart contracts and external APIs.

Conducted internal smart contract audits, testing, and deployments to testnets and mainnet.
Wrote unit and integration tests to ensure stability of smart contracts and application logic.

Collaborated with designers, blockchain engineers, and backend teams to deliver complete product features.

Read and worked with technical documentation in English.

Blocksport AG June 2022 – January 2023
Full Stack & Blockchain Developer

Developed smart contracts for NFT, ERC20, ERC721, ERC1155, and marketplace staking.

Created admin panel components and NFT platform interfaces using ReactJS.
Built blockchain listeners and WebSocket event handlers using Node.js.

Developed modules, microservices, and API endpoints for platform functionality.
Managed PostgreSQL databases using Sequelize.

Automated smart contract testing.

AVTO June 2021 – January 2022
Blockchain Developer

Developed smart contracts for DeFi exchanges.
Built front-end applications using ReactJS.
Created Node.js API parsers for blockchain data.

Performed internal smart contract audits.
Implemented automated tests using Truffle, Mocha, Chai, and Hardhat.

Erudito June 2020 – June 2021
Full Stack Developer
Developed RESTful APIs for CRM systems using Node.js and Sequelize.

Built CRM web applications with ReactJS.
Managed PostgreSQL databases using Sequelize.
Deployed applications using Docker and GitLab CI/CD.
Implemented Firebase push notifications and real-time database features.

Developed Viber bots and integrated DigitalOcean services.

MyRas.fr September 2019 – June 2020
Full Stack Developer France (remote)
Developed RESTful APIs using Node.js and PHP.
Built microservices with Node.js for high-load environments.

Created CRM applications using AngularJS.
Managed PostgreSQL databases.
Worked with high-load systems using Docker Engine API and AWS.

IPTeamCloud.com October 2018 – 2019
Full Stack Developer Kiev
Developed RESTful APIs using Node.js and MongoDB.

Built user account systems with ReactJS.
Integrated Macroscop CCTV systems.
Developed WHMCS-CRM modules using PHP.

Implemented Google Maps functionality.

AIVIA, Nous Platform, NOUS TOKEN November 2017 – October 2018
Full Stack & Blockchain Developer
Developed RESTful APIs using Node.js.
Created cron applications, parsers, and snapshot services using Node.js.

Built web applications with ReactJS.
Developed Solidity smart contracts and unit tests.
Contributed to the development of complex distributed systems.

InWeb24, Grosl, OneTravelTeam, MyDoctorCare.com, InWebGlobal, afisha.nyc etc. November 2014 – 2017
PHP and Node.js Programmer
Modified and extended open-source applications including WHMCS add-on modules.

Developed PHP/MySQL applications according to specifications.
Built admin websites using Angular, Sails REST API, and MongoDB.
Implemented and hosted systems on web servers.

Coordinated with team members to design and develop database structures.
Tested and analyzed programming projects and reported results.

Antarasoft 2013 – 2014
PHP Programmer Kharkov

Handled PHP backend development for dynamic, database-driven websites.
Developed WordPress plugins and supported existing projects.

Troubleshot and resolved issues with PHP and other web technologies.

Designed, developed, coded, tested, and debugged system requirements.
Performed tasks under the guidance of senior PHP programmers.

Teploavtomat 2012 – 2013
System Administrator & Web Developer Kharkov

Maintained smooth PC operations in the office environment.
Installed and configured internet networks.

Provided server support and monitoring.

Supported company websites and partner sites.

Education
Kharkov State Automobile and Highway University

Skills
Node.js & Backend
Node.js, TypeScript, NestJS, Express.js, REST API, Microservices, Async/Await, WebSockets, Background jobs, Queues, PHP

Frontend (React & Next.js)
React.js, Next.js, React Native, Redux, Reselect, redux-form, SPA, Performance optimization

Blockchain & Solidity
Solidity, Smart contracts, ERC-20, ERC-721, ERC-1155, DeFi, Web3.js, Ethers.js, Hardhat, Truffle

Databases & Caching
PostgreSQL, MySQL, MongoDB, Redis, Sequelize, Mongoose, Query optimization

DevOps & Cloud
Docker, Docker Compose, GitLab CI/CD, AWS EC2, AWS S3, NGINX, Linux

Tools & Practices
Git, GitHub, GitLab, Jira, Redmine, Code review, Unit tests, Integration tests, E2E tests, Jest, Mocha, Chai

Certifications
Certification Course in PHP Programming 2012
Master Class, Kharkov

Languages
Ukrainian

English
Pre-Intermediate — capable of reading and understanding technical documentation