Sayem A.

Top Rated Solidity & Web3 Developer | 100% Job Success | 900+ hours with long-term clients. I build secure, gas-optimized smart contracts and full-stack DeFi dApps for founders and technical teams who can't afford bugs in production. Most DeFi projects don't fail because of the idea. They fail because of a vulnerable contract, a confusing wallet flow, or a backend that can't keep up. I handle all three layers (smart contracts, Web3 frontend, and backend), so you get one developer who owns the whole system. 🛠️ WHAT I BUILD Smart Contracts & DeFi - Custom Solidity contracts built on OpenZeppelin standards and tested with Hardhat and Foundry - ERC-20, ERC-721 and ERC-1155 tokens, staking, vesting, yield farming, liquidity pools and token swaps - Security-focused development: access control, reentrancy protection and thorough testing before every deployment Web3 Frontend & dApps - React / Next.js dApps connected to the blockchain with Ethers.js, Viem and Wagmi - Wallet integration: MetaMask, WalletConnect, RainbowKit and Coinbase Wallet - Real-time DeFi dashboards for balances, positions, token management and on-chain analytics Backend & Infrastructure - Node.js / NestJS APIs (REST, GraphQL, WebSockets) for off-chain data, real-time market feeds and payments - Docker, CI/CD with GitHub Actions, AWS and Vercel deployment, JWT / OAuth authentication 🔗 CHAINS [Ethereum | Polygon | BNB Chain | Arbitrum | Base] 💻 TECH STACK Blockchain: Solidity, Hardhat, Foundry, OpenZeppelin, Ethers.js, Web3.js, Viem, Wagmi Frontend: React, Next.js, TypeScript, Redux, Tailwind CSS Backend: Node.js, Express, NestJS, REST & GraphQL Databases: MongoDB, PostgreSQL, Supabase DevOps: Docker, GitHub Actions, AWS, Vercel, Linux 💡 WHY CLIENTS KEEP WORKING WITH ME - Security first: in DeFi, a bug costs real money. I write defensive, well-tested code and flag risks before deployment, not after. - Full ownership: contracts, frontend and backend built by one developer, designed to fit together. - Reliable communication: milestone-based plans, regular updates, clean Git history and support after launch. Most of my clients hire me for long-term work. 🚀 NEXT STEP Send me your idea, wireframe or contract spec. I'll reply with a short technical plan covering architecture, timeline and the key risks to watch for.