Full-stack · Web3 · Mobile

Kyrylo Sotnykov

Senior Full-stack / Mobile Developer

+1 (573) 639-0479|kyrylo@sotnykov.com|Tampa, FL|LinkedIn

Objective

Full-stack / Mobile Developer with 7 years of professional experience building scalable applications for Web3, blockchain, and cloud-based environments. Strong expertise in React, React Native, and TypeScript with a track record of delivering high-quality user-facing products. Skilled in NestJS, Node.js, Docker, and cloud platforms such as AWS and IBM Cloud. Experienced with EVM, Bitcoin, and secure integrations using HSM. Passionate about innovation, collaboration, and continuous learning.

Education

Bachelor of Business Administration2017 – 2022

Odesa National Maritime University

Certifications

Full-stack DeveloperIBM · 2025
Generative AI with Large Language ModelsAWS · 2025
Blockchain SpecializationUniversity of Buffalo · 2025

Skills

Programming Languages

JavaScript, TypeScript, Solidity, Python, SQL

Technologies

React.js, Node.js, Nest.js, React Native, Vue.js, Flask, Docker, Blockchain

Soft Skills

Problem-Solving, Critical Thinking, Attention to Detail & Quality, Adaptability

Tools

OpenAPI, CI/CD, Jest, Terraform, Prometheus, AWS, IBM Cloud, Cursor

Experience

Guardian Labs

Remote · Ashland, MO

Aug 2024 – Present

Senior Full-stack Developer

  • →Developed secure APIs with NestJS, TypeScript, and HSM, increasing system reliability and reducing security risks by 75%.
  • →Built React and React Native applications that improved UX performance by 40% and reduced crash rates by 80% during beta testing.
  • →Led cross-functional delivery of Web3 projects integrating EVM and Bitcoin networks, resulting in 10x higher transaction throughput.
  • →Achieved 40% faster deployments and reduced production errors by automating CI/CD pipelines with Docker, GitLab CI, and AWS.

Lacero Platform Limited

Remote · London, UK

Jan 2023 – Aug 2024

Senior Full-stack Developer

  • →Developed a React Native self-custody wallet app, enabling offline transaction signing and biometric authentication, reducing user errors by 90%.
  • →Designed and implemented a non-custodial wallet backend using Node.js (NestJS) and microservices architecture, ensuring scalable key management, fault isolation, and high security for institutional users.
  • →Spearheaded infrastructure modernization by introducing Docker, GitLab CI, ESLint, Prettier, improving deployment reliability by 30%.

Lacero Platform Limited

Oct 2021 – Jan 2023

Middle Full-stack Developer

  • →Built React + TypeScript dashboards for digital asset management, cutting load times by 60% and scaling to 500 concurrent users.
  • →Created proof-of-concept apps with NestJS and WalletConnect, demonstrating innovative blockchain integrations from 0 to 1.

Nova Poshta Center

Remote · Kyiv, Ukraine

Jun 2021 – Oct 2021

Middle Full-stack Developer

  • →Led development of a document management system with e-signatures, improving processing efficiency by 35%.
  • →Delivered a Node.js + Vue.js service that automated document generation/signing, reducing manual errors by 70%.
  • →Built an internal portal with role-based access and ElasticSearch, which improved search functionality by 50%.
  • →Distributed tasks within a small dev team, boosting delivery speed and ensuring on-time launch under tight deadlines.

TR Logic LLC

Remote · Panama City, Panama

May 2020 – Jun 2021

Middle Front-end Developer

  • →Built a real-time messenger with chat, audio/video calls, and social login, increasing user engagement duration by 40%.
  • →Led a team of 3 developers using Vue.js and GraphQL, consistently meeting project deadlines.
  • →Optimized message history rendering via lazy loading, cutting bandwidth usage by 50%.
  • →Designed scalable UI components improving load speed by 70%, reducing churn rate in early testing.

JuJu Media

Remote · London, UK

Mar 2020 – May 2020

Middle Front-end Developer

  • →Implemented new features like room-specific panoramas and technical details using Vue.js and Fabric.js, improving user experience and providing detailed insights into room specifications.

MantiCore Development

On-site · Odesa, Ukraine

Dec 2019 – Mar 2020

Middle Front-end Developer

  • →Developed a car rental Progressive Web App (PWA) in Vue.js, enabling offline mode and increasing mobile traffic by 35%.
  • →Implemented API integrations that reduced data sync time by 55%.

MantiCore Development

Dec 2018 – Dec 2019

Junior Front-end Developer

  • →Created responsive websites with modern UI/UX, boosting client inquiries by 15% post-launch.
  • →Delivered projects ahead of schedule, improving customer satisfaction and securing follow-up contracts.

Projects

Keyper Vault Custodial Wallet

Developed a secure custodial wallet mobile app with React Native, NestJS, WalletConnect, and HSM. Optimized RPC requests for 300% faster processing, reduced infrastructure costs 3x, and improved crash rates by 80%. Deployed successfully to App Store and Google Play.

FlowOS B2B Digital Asset Platform

Built a platform for automated policy-driven transaction approvals using React, NestJS, and Solidity smart contracts. Reduced gas costs by 40%, improved dashboard load times by 60%, and enabled 500+ concurrent users without latency. Delivered 3 months ahead of schedule.

Open-source Document Verifier

Created a decentralized application for document authenticity verification on Ethereum and Polygon using Solidity, Hardhat, and React. Enabled users to register and validate proofs on-chain, adopted in open-source community.

Live Demo ↗

AI Trip Planner

Built a web app with Node.js, React, and OpenAI API that generates personalized itineraries from natural language input. Successfully used by travelers to automate trip planning.

Live Demo ↗

sign-proof NPM Library

Published an open-source JavaScript library for cryptographic signing and verifying data off-chain. Lightweight and efficient for Web3 and enterprise use cases, available on npm.

Package ↗

Leadership

  • Led small developer teams (2–4 engineers) at TR Logic and Nova Poshta Center to successfully deliver high-impact applications under tight deadlines.
  • Mentored junior developers on best practices in React, NestJS, and blockchain integrations, fostering knowledge-sharing and growth.
  • Initiated infrastructure optimization at Lacero by introducing CI/CD pipelines, Docker, and automated linting, which became company-wide standards.