Senior Fullstack Engineer

Location: Sao Paulo, Brazil

About the role
You will support and build Watu, a leading asset financier focused on mobility and connectivity. Watu provides financing for motorcycles, three-wheelers and smartphones across multiple markets, through systems built for scale, reliability and long-term use.
 

What you'll do

• Design, build, and run Java/Spring Boot services in production, from API contract to monitoring.
• Make architecture decisions and document them in ADRs so the reasoning outlives the conversation.
• Build reliable event-driven flows on Kafka or RabbitMQ, designing for retries, duplicates, and partial failure.
• Integrate with partners and financial institutions, including legacy SOAP/XML services.
• Review pull requests for design, maintainability, performance, and test coverage, not just style.
• Own the documentation for what you build: READMEs, runbooks, API specs.
• Mentor other engineers and take technical lead on projects.
• Full-stack track: build and maintain Angular front-end features end to end.

What you need

• 5+ years of professional Java, including at least 3 years making design decisions on production systems.
• Deep Spring Boot experience: dependency injection, Spring Security, Spring Data, transaction management, and testing.
• Solid REST API design: versioning, error handling, idempotency, pagination, and OpenAPI documentation.
• Strong relational database skills (PostgreSQL or MySQL): schema design, indexing, query optimization, and JPA/Hibernate, including knowing when to bypass the ORM.
• Production experience with Kafka or RabbitMQ: consumer groups, offset management, delivery semantics, and idempotent consumers.
• A practical grasp of distributed-system failure modes: eventual consistency, retries, circuit breakers, timeouts, and distributed tracing.
• Testing discipline: unit tests with JUnit and Mockito, integration tests against a real database, and a sense of what belongs at each level of the test pyramid.
• Comfort with Docker, CI/CD pipelines (we use Maven, Jenkins, and Git with mandatory PR review), and AWS.
• Security awareness: OWASP Top 10 and proper secrets management (AWS Secrets Manager, Vault, or similar).
• Regular use of AI coding tools for code generation, tests, debugging, and documentation, along with the judgment to verify what they produce.
• Professional working English.

Nice to have

• Fintech or payments experience, especially reconciliation, payment idempotency, and audit logging.
• Kotlin, or an interest in learning it.
• Avro or Protocol Buffers with a schema registry.
• WebSockets, Nginx, HAProxy, Tomcat.
• Report generation with JasperReports or xdocreport.
• Experience formally leading a team.

Full-stack track: additionally

• 2+ years with Angular and TypeScript, including RxJS, HTML, and SCSS (Bootstrap is a plus).
• Familiarity with front-end build tooling (Webpack, Babel).
• Bonus: AngularJS experience (we maintain some legacy code), React, or Vue.

How we work

• We clarify ambiguous requirements early instead of building the wrong thing well.
• We value "I'm not sure, let me check" over confident guesses.
• We treat code review as a design conversation.
• We write things down.

What we offer
Compensation range within market standards, contract type (CLT/PJ), benefits, global growth path