Senior Engineer - Fiat Payment，Card

About the OKX Card Team
The OKX Card Team builds the payment infrastructure connecting digital assets to global commerce. Partnering with major card networks like Visa and Mastercard, we power the OKX crypto card platform. Our team handles the full card lifecycle and payment stack—from instant issuance and real-time transaction authorization (Auth) to settlement, ledger management, and card growth engines. We also actively embrace AI-assisted development to build fast, scale cleanly, and maximize engineering velocity.

Key Responsibilities
- Core Card Services: Develop and maintain reliable backend microservices in Java for card issuing, authorization pipelines, and settlement clearing.
- Workflow Orchestration: Utilize Temporal to manage complex, multi-step transaction lifecycles and resilient distributed state machines.
- Data & Ledgers: Design and optimize SQL schemas and queries to ensure exactness and speed across high-concurrency transaction ledgers.
- AI-Enhanced Velocity: Integrate modern AI development tools into your daily workflow to speed up coding, unit testing, and problem-solving.
- Growth & Features: Deliver features for promotional campaigns, rewards, and card lifecycle management to support user growth.

Qualifications
- Technical Core: 1–3 years of backend engineering experience proficient in Java (Spring Boot) and relational databases via SQL.
- Workflow Management: Direct experience or solid understanding of distributed workflow tools like Temporal (or Cadence).
- Card & Fintech Domain: Strong background in Fintech with a solid grasp of card transaction mechanics (Visa/Mastercard networks, Auth, clearing, and issuing workflows).
- AI Tooling Mindset: Proactive in using AI development tools (e.g., Copilot, AI assistants) to boost output and maintain high code quality.
- Soft Skills: Highly self-driven, quick learner, and excited to build secure financial products.

Nice to Have
- Experience working directly with Card Issuing processors or Payment Service Providers (PSPs).
- Broad understanding of Web3 concepts or crypto-to-fiat conversion flows.
- Exposure to cloud-native stacks (Docker, Kubernetes, AWS/GCP).