Wallet Engineer

Build secure, reliable, and scalable wallet integrations and transaction flows for the Biti platform, focusing on connectivity, signing, and execution across multiple chains. Location: Remote / Work from Home Type: Part-time preferred / Full-time available Responsibilities - Integrate major Web3 wallets (e.g., MetaMask, WalletConnect, Coinbase Wallet) across web and mobile environments - Design and implement secure transaction signing pipelines (EIP-1559, EIP-712, typed data, permit flows) - Build robust wallet connection systems, including session persistence, reconnection, and multi-account handling - Implement transaction building logic, including calldata construction, batching, and multi-step execution flows - Develop gas estimation, fee optimization, and fallback strategies across different networks - Handle edge cases such as nonce management, transaction replacement (speed up / cancel), and re-org scenarios - Collaborate with backend teams on routing, simulation, and execution layers - Work closely with frontend teams to ensure seamless UX for wallet interactions and transaction confirmations - Ensure high security standards in key handling, signing flows, and user interaction surfaces Requirements - Strong proficiency in JavaScript / TypeScript - Hands-on experience with Web3 libraries (ethers.js, viem, web3.js) - Deep understanding of EVM transaction lifecycle and structure - Experience implementing wallet connection and signing flows in production - Familiarity with RPC providers, node inconsistencies, and network reliability issues - Experience building or contributing to Web3 applications (DEX, wallet, aggregator, etc.) Nice to Have - Experience with multi-chain environments (Ethereum, Arbitrum, BSC, Polygon, etc.) - Familiarity with account abstraction (ERC-4337) - Experience with smart contract interaction patterns (multicall, proxy, upgradeable contracts) - Understanding of MEV, slippage, and transaction execution risks - Experience working on DeFi protocols or trading-related products