Yuriy G.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.

As of Nov 2026, I am available. Invite me to discuss your project. I develop Solidity smart contracts with a focus on security, correctness, maintainability, and gas efficiency. I bring many years of software development experience and a meticulous approach to edge cases. I specialize in smart contracts rather than web development, giving the mission-critical contract logic my full attention. Cosmic Signature: my flagship smart contract project I developed smart contracts for Cosmic Signature, an on-chain bidding game and token ecosystem on Arbitrum. Highlights: - A UUPS-upgradeable game contract, developed across multiple versions, with ETH and ERC-20 token bidding, Dutch-auction pricing, and prize distribution. - The game's own ERC-20 token for bidding and voting, ERC-721 NFTs, and DAO governance built on OpenZeppelin contracts. - NFT staking with ETH rewards, prize withdrawals, and wallets for prizes, donations, charity, and marketing. - Hardhat tests with Ethers.js and Mocha, contract model-based fuzz testing, upgrade checks, and deployment tooling. I put substantial effort into design and testing before external review. The audited contract version remained unchanged following Hacken's audit; findings were accepted or mitigated. My portfolio links to the source code, audit report, and website. How I work - I take ownership of the work, keeping your business goals and budget in view. - I communicate regularly about progress, tradeoffs, and decisions that need your input. - I use AI tools while taking responsibility for reviewing and validating the work I deliver. - I prioritize value on hourly contracts and do not bill for learning material I should already know. - I focus on one project at a time so your work has my full attention. - I speak English, Russian, and Ukrainian, and can align my working hours with European time zones. - I respect your confidentiality and intellectual property.