Open to opportunities

Oleksandr Tuvshyntur

@alextuvshyntur

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Full-stack blockchain and Web3 engineer specializing in secure smart contracts.

Ukraine

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What I'm looking for

I am seeking senior-level roles building secure, scalable Web3 and full-stack products where I can lead architecture, improve security, and deliver measurable product growth.

I am a results-driven software engineer with 7+ years spanning blockchain, web, and mobile development, delivering secure, scalable smart contracts on Ethereum, BSC, Solana and production-ready full-stack platforms.

I've led end-to-end projects: architecting upgradeable Solidity and Rust contracts, building React/Next.js web apps, and shipping cross-platform mobile apps with React Native and Flutter, driving measurable product improvements like a ~25% uplift in rental conversions.

I emphasize secure, maintainable systems through audits, testing (Hardhat/Foundry), CI/CD, and thorough documentation, and I collaborate closely with product, UX, and backend teams to deliver reliable, user-focused Web3 and enterprise solutions.

Experience

Work history, roles, and key accomplishments

Current

Mobile App Developer

Current

Big Rentals Inc

Jul 2025 - Present (5 months)

Led full-lifecycle development of cross-platform mobile applications using React Native, integrating payments, real-time booking and notifications to drive a ~25% uplift in rental conversion and reduce app load times by ~30%.

React Native Flutter Push Notifications Geolocation Performance Profiling Payments Agile Scrum

Senior Web Developer

Unique Leverage LLC

Jul 2024 - May 2025 (10 months)

Designed and implemented scalable React/Next.js web applications and real-time dashboards, improving organic traffic by 40% and serving thousands of daily active users through optimized SEO and API integrations.

React Next.js TailwindCSS WebSockets Redux SEO CI CD API Integration

Senior Smart Contract Developer

Arrow Markets

Jun 2022 - Nov 2024 (2 years 5 months)

Designed and maintained Solidity smart contracts and upgradeable proxy patterns for an on-chain options marketplace on Avalanche C-Chain, conducting audits and testing to reduce protocol risk prior to mainnet deployment.

Solidity Hardhat Foundry Upgradeable Proxies Smart Contract Auditing Avalanche Testing

White Hat Hacker

Immunefi

Dec 2018 - Apr 2019 (4 months)

Performed penetration testing and vulnerability research on decentralized protocols, disclosing critical smart contract exploits and producing PoC exploits and remediation reports to prevent multi-million-dollar risks.

Vulnerability Reports Oracle Manipulation Reverse Engineering

Education

Degrees, certifications, and relevant coursework

Kharkiv National University of Radio Electronics

Bachelor of Engineering, Computer Software Engineering

2014 - 2018

Activities and societies: Internships and collaborative projects; version control (Git) experience.

Bachelor of Engineering in Computer Software Engineering with coursework in software engineering, system architecture, algorithms, databases, and a capstone web-based task management project.

Rivne State Humanitarian University

Bachelor of Science, Information Technology

2010 - 2012

Activities and societies: Projects on network setup, data backup strategies, and team-based IT infrastructure work.

Bachelor of Science in Information Technology covering computer networks, operating systems, information security, and introductory programming with practical LAN/WAN and IT support projects.