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