Sergey C.

I’m a blockchain architect and hands-on engineer helping founders and engineering teams build Web3 products — from RWA tokenization, stablecoins, and DeFi to prediction markets and investment platforms. I also build custodial/non-custodial wallets and crypto payment systems. My work covers technical discovery, smart contract architecture, backend integrations, and deployment. I connect on-chain logic with identity verification, custody providers, oracles, internal ledgers, and transaction processing. I collaborate with security auditors including CertiK on audit preparation and remediation. My approach focuses on clear architecture, secure contracts, testing, and maintainability. 🏆 HOW I CAN HELP ✓ Blockchain Architecture — feasibility, requirements, on-chain/off-chain architecture, protocol design, and implementation planning. ✓ RWA & Stablecoins — asset tokenization, security tokens, tokenized funds, minting/redemption, reserve integrations, investor onboarding, transfer restrictions, and pricing. ✓ DeFi — DEXs, AMMs, liquidity pools, staking, yield farming, lending/borrowing, and vaults. ✓ Prediction Markets — market creation/resolution, smart contracts, oracles, settlement, and rewards. ✓ Crypto Payments & Custody — payment gateways, invoicing, fiat on/off-ramps, payment/custody integrations, internal ledgers, reconciliation, monitoring, and KYC/AML. ✓ Investment & Portfolio Platforms — investment workflows, asset tracking, dashboards, rebalancing, analytics. ✓ Wallets — custodial/non-custodial wallets, smart accounts, account abstraction, signing. ✓ Smart Contracts & Infrastructure — Solidity, Rust, Move; testing, security hardening, gas optimization, APIs, indexers, data pipelines, cross-chain integrations, and deployment. 🚀 HIGHLIGHTED PROJECTS Gold-Backed Stablecoin — Liechtenstein Ethereum/Polygon stablecoin infrastructure with fiat and on-chain/off-chain integrations. ✓ Sumsub KYC, whitelisting, transfer restrictions ✓ PayPal/bank fiat integrations ✓ Oracle and OTC gold pricing ✓ Mint/burn and reserve audit workflows ✓ Storage fees through token balance decay ✓ Custom EVM network support Solana DEX Aggregator & Trading Terminal — NDA Trading platform with swaps, limit orders, charts, launchpad tokens, and tokenized stocks. ✓ Raydium, Orca, Meteora integrations ✓ Fee/slippage-aware quotes ✓ Limit order execution ✓ Wallet connectivity and transaction status Real Estate Tokenization — ERC-3643 & OnchainID Security token infrastructure built with Solidity, Hardhat, TypeScript, ERC-3643 (T-REX), and OnchainID. ✓ Investor identity and KYC claims ✓ Country, supply, balance, and time-based compliance rules ✓ CREATE2/CreateX deployment ✓ Automated issuance and verification Crypto Price Prediction Game — BNB Smart Chain & Solana PancakeSwap-style prediction game with timed rounds, settlement, prizes, and referrals. ✓ BSC/Solana mechanics ✓ Betting, price capture, and settlement ✓ Oracle integrations ✓ Bet tracking and prize distribution ✓ Fee accounting and multisig wallets ⚙️ TECHNOLOGY Smart Contracts: Solidity, Rust (Solana), Move (Aptos/Sui) Frameworks & Security: Foundry, Hardhat, Anchor, Truffle, Slither, Mythril, Echidna, Certora Blockchains: Ethereum, Polygon, BNB Chain, Arbitrum, Optimism, Avalanche, Solana, TON, TRON Backend: Node.js, NestJS, PostgreSQL, Redis, RabbitMQ, Kafka On-Chain Data: The Graph, SubQuery, custom indexers Infrastructure: Docker, AWS, GCP, CI/CD, blockchain nodes Monitoring: Prometheus, Grafana, Alertmanager Integrations: Chainlink, Safe, Fireblocks, Sumsub, OnchainID, Raydium, Orca, Meteora, PayPal Token Standards: ERC-20, ERC-721, ERC-1155, ERC-4626, ERC-7540, ERC-3643, ERC-1400, ERC-1404, ERC-7518, ERC-7943 Account Abstraction: ERC-4337 Signatures: EIP-712, ERC-1271 Identity: OnchainID 💬 DISCUSS YOUR PROJECT Share your idea, requirements, or existing codebase. In a free 40-minute consultation, we can discuss your architecture, technical risks, and next development milestone. Keywords: Blockchain Architect, Blockchain Developer, Web3, Smart Contracts, Solidity, Rust, Move, EVM, Ethereum, Solana, TON, TRON, RWA Tokenization, Real Estate Tokenization, Stablecoins, ERC-3643, ERC-1400, ERC-7943, OnchainID, DeFi, DEX, AMM, Uniswap v4 Hooks, Staking, Yield Farming, Lending, Tokenized Vaults, Prediction Markets, Crypto Payments, Crypto Invoicing, Fiat On/Off-Ramp, Custody, Investment Platforms, Portfolio Management, Blockchain Analytics, Crypto Wallets, Account Abstraction, ERC-4337, EIP-7702, Smart Contract Security, Audit Preparation, Gas Optimization, Oracles, Chainlink, Foundry, Hardhat, Anchor, The Graph, Blockchain Indexing, Backend, Multi-Chain Deployment.