The Role
The Lead Java Developer will design and maintain payment systems, implement secure transaction flows, and develop microservices while ensuring compliance and performance across financial platforms.
Summary Generated by Built In
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:
Key Responsibilities
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.
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.
- 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).
- Full-time employment with a formal contract.
- Competitive salary and performance-based annual bonus.
- Opportunity to grow within a global fintech leader.
Top Skills
Docker
Grpc
Hibernate
Java
Jpa
Kafka
Kubernetes
Maven
Mybatis
Postgres
Restful Apis
Spring Boot
Spring Cloud
Websocket
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The Company
What We Do
Mamoru is a leading global fintech solutions group. Our goal is to provide an all-rounded solution to facilitate easiest access to assets and products with our proprietary technology and global coverage. Our team is built from technology, market making and venture capital backgrounds.
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