This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Fullstack Software Engineer based in Brazil. This is an opportunity for a senior engineer to build and evolve scalable, reliable fullstack applications within a data-driven technology environment.You will work across frontend and backend layers, contributing to products that help businesses make better-informed decisions.The role combines hands-on software development with a strong focus on application performance, reliability, monitoring, and production excellence.You will use technologies such as ReactJS, NodeJS, NestJS, MongoDB, and PostgreSQL to deliver robust SaaS and platform solutions.Beyond feature development, you will investigate incidents, perform root cause analysis, and help strengthen systems against future failures.You will collaborate closely with engineering teams in an agile environment where clean code, testing, scalability, and continuous improvement are highly valued.This role is well suited to an experienced fullstack engineer who enjoys solving complex technical challenges and building dependable products at scale.