Vitaliy R.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

I help founders and product teams design, build, review, and ship EVM smart contract systems — from product idea and protocol architecture to implementation, testing, deployment, and audit readiness. I have 5 years of hands-on Solidity development experience and 5+ years of prior software engineering / QA experience in fintech and banking-related environments. That background makes me especially strong in correctness, edge cases, test design, review discipline, and production-minded delivery. What I can help with: - smart contract architecture and implementation - protocol review and internal security-focused code review - full Foundry / Hardhat test suites - refactoring or full rework of existing smart contract systems - ERC20 / ERC721 / ERC1155 / ERC4626-based development - DeFi, vault, staking, token, wallet, escrow, vesting, and marketplace logic - deployment scripts, verification, and environment setup - backend / frontend integration support (ABI flows, contract interactions, event/indexing guidance) - audit preparation, documentation, NatSpec, and cleanup before third-party review My typical stack includes Solidity, Foundry, Hardhat, Ethers.js, OpenZeppelin, Solady, Slither, Tenderly, Chainlink, and Ethereum / EVM-compatible chains and L2s. I work well in two modes: 1. taking a project from scratch and building the blockchain direction end-to-end 2. reviewing an existing implementation, identifying weaknesses, and driving a strong cleanup or rework I have experience across stablecoin, vault, staking, token, NFT, smart wallet, escrow, and other custom protocol flows. If you need a Solidity developer who combines product understanding, engineering discipline, and strong testing habits, I’d be glad to help.