Staff/Senior Java Engineer, OKX Web3 Wallet

Staff/Senior Java Engineer, OKX Wallet (Web3) Who We Are OKX Wallet is OKX's self-custody wallet, built for users worldwide to securely and conveniently store, manage, and use their on-chain assets. The wallet backend operates in a multi-chain, multi-asset, high-concurrency environment shaped by on-chain state uncertainty and strict fund-security requirements — combining the complex-systems challenges of traditional internet backends with the transaction, signing, and on-chain interaction problems unique to blockchain. We're looking for a Senior Java Engineer with roughly 5–10 years of backend experience: someone with strong engineering fundamentals who can independently own core modules, exercise sound judgment on complex problems, and proactively coordinate across upstream and downstream teams to drive work to completion. What You'll Do Own core wallet backend modules. Build and continuously improve address management, asset synchronization, transaction construction, broadcasting, on-chain confirmation, gas estimation, nonce management, and transaction-state tracking. Understand each module's role in the full wallet flow, and keep stability, performance, and maintainability front of mind. For complex requirements, break the problem down before choosing an implementation rather than stacking code or reusing old designs. Build transaction and on-chain interaction scenarios. Work on transfers, token approvals, contract interactions, cross-chain, swaps, DApp connections, and signature-request handling. Understand a transaction's full lifecycle — from initiation through construction, signing, broadcasting, on-chain confirmation, and final state update — and diagnose issues like stuck transactions, duplicate submissions, state inconsistencies, and on-chain success that isn't reflected in the business system, using logs, on-chain data, and call traces. Support multi-chain and new-chain integration. We already support EVM, Tron, and Solana, and continuously onboard