Backend Developer (Shopify, NestJS, Spring Boot, SQL)

We are seeking a Senior Java Backend Developer to architect and lead the development of a mission-critical Middleware System. This system acts as the high-performance nerve center connecting our global e-commerce frontends (Shopify Plus) with enterprise-scale internal legacy systems (ERP, SAP, POS, OMS).In this role, you will not just write code; you will design scalable architectures using Java (Spring Boot) and TypeScript (NestJS), solve complex O2O (Online-to-Offline) integration challenges, and ensure data integrity across multiple international markets. We are looking for a technical leader who thrives on building robust systems that handle high-volume traffic with precision. 1. Architecture & Technical LeadershipSystem Design: Lead the architectural design of scalable middleware services, utilizing a hybrid stack of Java 17+ (Spring Boot 3.4) for heavy processing and TypeScript (NestJS) for agile gateway services.Code Quality & Mentorship: Enforce high standards for code quality through rigorous code reviews, TDD implementation, and mentoring of junior developers.Solution Engineering: Translate complex business requirements into technical solutions that ensure seamless synchronization between Shopify and legacy enterprise systems.2. Complex Integration & Data ManagementAPI Ecosystem: Design and implement robust RESTful and GraphQL APIs to orchestrate data flow between external platforms and internal ERP/POS systems.High-Volume Processing: Engineer reliable batch processing and event-driven architectures (using RabbitMQ) to handle massive real-time updates for inventory, orders, and fulfillment.Database Optimization: Design efficient database schemas and perform advanced query tuning on RDBMS (PostgreSQL, MySQL, etc.) to ensure sub-second response times under load.3. DevOps & Operational ExcellenceReliability & Monitoring: Proactively monitor system health using APM tools (Datadog, OpenSearch) and lead root-cause analysis for performance bottlenecks.CI/CD Pipelines: Maintain and optimize automated deployment pipelines using GitLab CI, Jenkins, and AWS CodeDeploy.Internal Tools: Oversee the development of admin dashboards (Thymeleaf/HTMX) to support operation teams.