Senior Java Engineer – Web3 Wallet

About the role

OKX Wallet is a self‑custody, multi‑chain wallet serving users worldwide. We are looking for a senior Java engineer with 5–10 years of backend experience to own core wallet modules and drive high‑concurrency, security‑critical features.

Key responsibilities

• Design, implement and maintain core backend modules such as address management, asset sync, transaction construction, broadcasting, gas estimation and nonce handling.
• Build and troubleshoot transaction lifecycles, including transfers, token approvals, contract calls, cross‑chain swaps and DApp interactions.
• Support integration of new public chains, layer‑2 networks and asset standards, handling differences in address models, signing methods and fee structures.
• Ensure stable operation through monitoring, alerting, rate‑limiting, graceful degradation, retries and data reconciliation.
• Drive projects end‑to‑end, coordinate with product, QA, frontend and infrastructure teams, and resolve dependencies and risks.
• Participate in design reviews, code reviews and system optimisations, documenting decisions and post‑incident learnings.

Required profile

• 5–10 years of solid Java backend experience with deep knowledge of collections, concurrency, thread pools, JVM performance and network communication.
• Strong system‑design skills for high‑concurrency, idempotent and fault‑tolerant services.
• Ability to independently own modules from design through launch and to troubleshoot production incidents.
• Understanding of blockchain concepts such as addresses, keys, transaction signing, gas, nonce and token standards (EVM, Tron, Solana).
• High security awareness for private‑key handling, replay protection and least‑privilege principles.

Required skills

• Java
• Spring Boot, Spring Cloud
• MyBatis (or comparable ORM)
• Concurrency, thread pools, JVM tuning
• Message queues, caching, distributed locks, rate limiting
• Blockchain protocols (EVM, Tron, Solana) and token standards (ERC‑20, TRC‑20)
• AI coding assistants (Claude Code, Cursor, Codex) for code generation and review

What we offer

• Competitive total compensation
• Comprehensive insurance coverage for you and dependents
• Additional benefits discussed after joining