Senior Java Software Engineer

Senior Software Engineer (Java / Treasury Platform) Project Helios — Next-Gen Treasury System Location: Hong Kong (Looking for candidates available to start immediately) About Lightnet Lightnet Group is a leading Fintech enterprise headquartered in Singapore with a global footprint across APAC and Europe. We build next-generation financial infrastructure to bridge legacy banking rails with digital-asset liquidity, delivering real-time cross-border payments, settlement platforms, and financial services for institutional clients, SMEs, and digital-native businesses. We are expanding our core engineering team in Hong Kong to build Project Helios—Lightnet’s next-generation, real-time Treasury and On/Off-Ramp Platform. Helios serves as the high-throughput engine managing multi-currency liquidity, automated double-entry ledger systems, inventory-book netting, and smart order routing across international banking partners and institutional digital-asset venues. The Role We are seeking a Senior Java Developer to drive the technical design and backend delivery of Project Helios. In this role, you will architect and build low-latency, resilient distributed treasury services using cutting-edge Java technologies. You will work on various micro-services or components, including pricing engine, order execution engine, risk & hedging engine, settlement, custody and accounting services. Key Responsibilities ● Core Platform Development: Architect, build, and maintain high-performance, real-time backend microservices for Project Helios using Java 25 (Virtual Threads), Reactive Java, and Spring Boot. ● System Design & Event-Driven Architecture: Design event-driven workflows utilizing asynchronous message queues and distributed caching for order lifecycle state machines, real-time price stream ingestion, and inventory-book hedge triggers. ● Financial Ledger & Transaction Integrity: Design and maintain immutable, secure double-entry ledger systems and automated EOD reconciliation engines backed by PostgreSQL. ● Integrations Engine: Implement robust integrations via gRPC/REST/WebSockets with digital-asset custodians, liquidity provider rate streams, and commercial banking APIs. ● Testing & Quality Ownership: Drive high test coverage and platform reliability using Behavior-Driven Development (BDD) and Test-Driven Development (TDD) methodologies. ● Cloud & DevOps Practice: Package, deploy, and monitor scalable cloud components on AWS. Collaborate on CI/CD pipelines, automated deployments, and operational monitoring. Mandatory Skills & Experience ● Education: Bachelor’s degree in Computer Science, Software Engineering, or a related quantitative field. ● Backend Expertise: 5+ years of software development experience, with deep expertise in modern Java (Spring Boot, Dependency Injection, Object-Relational Mapping via JPA/Hibernate). ● Modern Java Paradigms: Hands-on experience or strong working knowledge of modern Java features, including Java 25 / Virtual Threads (Project Loom) and Reactive Programming (e.g., Spring WebFlux, Project Reactor). ● Messaging & Caching: Strong background with asynchronous message queue technologies and high-speed, in-memory data stores (Redis) for caching, distributed locking, or pub/sub patterns. ● Databases & Data Integrity: Advanced SQL and relational database experience (PostgreSQL), with a solid grasp of transaction isolation, distributed locking, and schema design for financial integrity. ● Quality & Testing: Proven experience with BDD (e.g., Cucumber) and TDD frameworks within automated CI/CD pipelines. ● Cloud & Infrastructure: Experience deploying and operating applications on AWS using Docker and containerized environments. ● Communication: Excellent spoken and written English communication skills. Ideal Additional Skills & Experience ● AI-Assisted Engineering: Hands-on experience leveraging AI coding tools (e.g., GitHub Copilot, Cursor, Claude Code, or 'vibe coding' workflows) to accelerate development, boilerplates, refactoring, and test generation. ● Domain Knowledge: Prior exposure to FX, Treasury management, Double-Entry Ledgers, Cross-Border Payments, Remittance, or Digital-Asset / Crypto On-Off Ramp systems. ● API & Connectivity: Hands-on experience integrating with third-party Liquidity Providers, banking APIs, or digital-asset institutional custody solutions. ● Security & Infrastructure: Familiarity with secure coding practices (OWASP), secrets management, Infrastructure as Code (Terraform), and Linux environments. What Lightnet Offers ● High-Impact Greenfield Project: Direct ownership over a mission-critical Treasury platform (Helios) utilizing a modern technology stack. ● Global Innovation Culture: An innovative, inclusive, flat organization with collaborative teams across APAC and international fintech hubs. ● Flexibility & Growth: Flexible work environment in our Hong Kong office, competitive compensation package, and ongoing professional development support.