Lead Java Developer (Brazil)

**Location: São Paulo, Brazil** **About Mamoru:** Mamoru is a dynamic global Fintech Payments group. Our goals are to provide an all\-rounded solution to facilitate the easiest access to finance and asset management products with our state\-of\-the\-art technology powered by blockchain and global coverage. The team is a group of talents from technology, market making and venture capital backgrounds. **Role Summary:** We are seeking an experienced Senior Java Developer with strong expertise in payment systems and banking API integration. The successful candidate will design and build mission\-critical services that power our financial infrastructure including digital wallets, real\-time settlements, reconciliation processes, and bank connectivity. You will collaborate closely with product compliance, and DevOps teams to ensure high availability, performance, and regulatory compliance across our platform. **Key Responsibilities** * Design, develop, and maintain high\-performance Java microservices for payment processing and financial transactions. Integrate with banking APIs, PSPs, and payment gateways (e.g., SWIFT, FPS, SEPA, VISA/MASTERCARD, or local clearing systems) * Implement secure payment and settlement flows, including authorization, posting, reconciliation, and refund logic * Work with event\-driven architecture using Kafka and apply event\-sourcing design patterns where appropriate * Ensure data integrity and transactional consistency across multiple systems (PostgreSQL, message brokers, and external APIs) * Build and maintain RESTful APIs and WebSocket services; implement gRPC integrations when needed * Collaborate with DevOps engineers on containerization (Docker), orchestration (Kubernetes), and CI/CD pipelines. * Participate in code reviews, testing, and monitoring improvements to ensure system stability and scalability * Support compliance with security and regulatory requirements, including PCI\-DSS, KYC/AML, and Open Banking standards **Requirements** * 8\+ years’ experience in Core Java for enterprise application development, with strong knowledge of Spring Boot, Spring Cloud, and event sourcing * Proficient in Kafka, JPA/MyBatis/Hibernate, Maven, and PostgreSQL (schema design, query optimization, data migration) * Hands\-on experience building RESTful APIs, WebSocket services, and familiarity with gRPC, Docker, Kubernetes, and microservice architectures * Skilled in JUnit 5, Mockito, and writing maintainable test suites * Good understanding of Git, CI/CD pipelines, and OAuth 2\.0/OpenID Connect * Experience in financial systems, banking integrations, or payment platforms is highly valued; knowledge of double\-entry accounting or reconciliation is a plus * Exposure to cloud platforms (AWS, GCP, or Azure) and contribution to open\-source projects is an advantage * Strong analytical, problem\-solving, and communication skills, with a commitment to clean code, testing, and continuous improvement * Self\-motivated, detail\-oriented, and able to work independently or collaboratively in a fast\-paced environment * Bachelor’s degree in computer science, Software Engineering, or related discipline; fluent in English (spoken and written) **What We Offer:** * Full\-time employment with a formal contract * Competitive salary and performance\-based annual bonus * Opportunity to grow within a global fintech leader Powered by JazzHR ilLQ3jlYxi