Job Summary: You will design and scale innovative and secure systems to solve real-world, high-impact problems, applying engineering best practices, AI, and continuous learning. Key Highlights: 1. Develop and maintain the Mercado Pago payment experience 2. Lead challenging, dynamic, and innovative projects 3. Collaborate with multidisciplinary teams As a **Senior Software Engineer Backend** at Mercado Livre, you will design and scale innovative and secure systems that solve real-world, high-impact problems. You will work in a dynamic environment powered by cutting-edge technology, applying engineering best practices, proprietary AI models, and continuous learning — all aimed at democratizing e-commerce and financial services across Latin America. Our team is responsible for developing and maintaining the Mercado Pago payment experience, with a special focus on the checkout flow via transfers. We tackle highly complex technical challenges to ensure millions of transactions across Latin America are fast, intelligent, and secure. Imagine yourself leading challenging, dynamic, and innovative projects and **being responsible for:** * Writing high-quality code, performing complex refactors, and conducting code reviews. * Designing and maintaining robust, scalable APIs to ensure resilient, modular solutions aligned with business objectives. * Collaborating with multidisciplinary teams (Product, Frontend, Data, SRE/Platform) for end-to-end delivery. * Making data-driven decisions using dashboards, analytical tools, and the team’s collective experience. * Designing distributed architectures using advanced patterns. * Defining testing and observability strategies, implementing automated tests, metrics, and logs to ensure reliability and performance. **What we’re looking for:** * Solid experience in similar roles, with proficiency in languages such as Java, Golang, and/or Python. * Knowledge of relational and non-relational databases, and observability tools such as Datadog and Grafana. * Experience designing and developing distributed architectures and microservices. * Experience with testing, ensuring high security standards. * Experience with an IDE/AI assistant (e.g., Cursor, Claude Code, Windsurf) and incident resolution will be considered advantages. **Are you excited to leave your mark on Latin America’s technology landscape?** Apply now and join our purpose! Work mode: Hybrid. Office: Osasco – SP.