Staff/Senior Java Engineer, OKX Web3 Wallet

About this role

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 new public chains, Layer 2 networks, and asset standards. Contribute to technical research, integration design, and feature development, accounting for differences in address models, account systems, transaction structures, signing methods, fees, and confirmation mechanisms — as well as node stability, asset sync, exception compensation, monitoring, and security boundaries.

• Ensure stable operation. Contribute to day-to-day stability work — monitoring, alerting, rate limiting, graceful degradation, retries, compensation, data reconciliation, and troubleshooting. When incidents occur, help investigate, narrow scope, and fix root causes; for recurring issues, drive systemic fixes such as added monitoring, stronger fallbacks, or design improvements.

• Drive your projects to delivery. Take ownership of the modules and projects you're responsible for. On work spanning product, QA, frontend, infrastructure, or other backend teams, proactively sync information, surface dependencies and risks, and drive issues to resolution. When requirements are unclear or opinions diverge, lay out the context, offer your own judgment, and help build consensus.

• Continuously raise engineering quality. Participate in design discussions, code reviews, and system optimization. Spot unreasonable designs, duplicated logic, and latent risks, and propose actionable improvements. Document technical decisions, post-incident learnings, and best practices, and help less-experienced teammates.

• Apply AI in daily development. Use AI coding tools (Claude Code, Cursor, Codex, etc.) to assist with code comprehension, scaffolding, unit tests, code review, troubleshooting, refactoring, and documentation — validating AI output for correctness, project conventions, performance, and security rather than using it unchecked.

What We're Looking For

• Solid Java backend fundamentals. ~5–10 years of Java backend experience with a strong grasp of collections, concurrency, thread pools, the JVM, network communication, and common performance…