Jefferson Valandro

Contract software engineer on client projects: Java and Spring Boot backends, REST APIs, React frontends and cloud infrastructure.

• Build backend services and REST APIs in Java 21 and Spring Boot.
• Deliver complete features from backend to React frontend, working with client teams.

Java 21Spring BootReactOracleCloud

Backend for mission-critical payment processing systems at a banking-sector client, focused on performance, security and high availability.

• Built and maintained payment-flow microservices in Java 17/21 and Spring Boot, with REST APIs and Oracle.
• Applied hexagonal architecture and asynchronous RabbitMQ messaging between services.
• Wrote unit and integration tests with JUnit and Mockito and monitored logs to find and fix production failures.
• Worked on Jenkins CI/CD pipelines in Scrum teams.

Java 21Spring BootRabbitMQOracleJUnit / MockitoJenkins

Technical leadership of a multidisciplinary team on Java educational software, responsible for architecture, code quality and team standards.

• Led the multidisciplinary team technically across the educational software projects.
• Drove architecture and development of scalable Java systems, ensuring code quality and best practices.
• Defined coding standards, technical guidelines and development strategies.
• Coordinated integration with infrastructure and information security across multiple environments.

JavaStrutsHibernate / JPAPostgreSQLJenkinsiReports

Modernization of the company ERP, focused on performance, scalability and reliability, plus backend automation of business processes.

• Led ERP modernization initiatives focused on performance, scalability and reliability.
• Built backend features and automated business processes.
• Kept third-party integrations working and production environments highly available.

Java 11+Spring BootRabbitMQDockerKubernetesPostgreSQL

Support and evolution of a transport company's ERP.

• Diagnosed operational issues, updated the ERP and implemented process improvements for transport operations.

Java 8SpringJSPiBatisPostgreSQL

Integrations between internal and external systems and evolution of a legacy ERP, with Java backend services for orders and automation.

• Integrated REST and SOAP APIs across internal and external systems, including payment gateways and messaging platforms.
• Maintained and evolved a legacy ERP in Visual DataFlex, adding features and improving stability.
• Contributed Java backend services for order management and business process automation.

Java 11+Spring BootREST / SOAPRabbitMQOracleVisual DataFlex

Six years on the company ERP: order workflows, integrations with external platforms and evolution of critical features.

• Managed order workflows and built Java integrations between ERP modules and external platforms.
• Evolved critical ERP features with a focus on stability, performance and maintainability.
• Took part in REST and SOAP integration projects, improving connectivity and data consistency between systems.

JavaSpring BootJSF / PrimefacesPostgreSQLJUnitJenkins

First role as a programmer, on the EducaWeb education system and on data integration between schools and government.

• Coordinated the data integration project between schools and government, streamlining communication between systems.
• Was a key contributor to the company's adoption of Scrum.

Java 7SpringJSPiBatisPostgreSQLScrum