Backend Developer Cover Letter Examples

Dear Sr. Almeida,

I am excited to apply for the Backend Developer position at Nubank. As a Brazil-based software engineer with a strong background building scalable, secure backend services for fintech and e-commerce products, I am enthusiastic about contributing to Nubank's mission of simplifying financial services and expanding access to digital banking across Latin America.

Over the past six years I have designed and implemented microservices and APIs using Java (Spring Boot), Kotlin, and Node.js, and I have production experience with PostgreSQL, Redis, Kafka, Docker, and Kubernetes on AWS and GCP. At PayCasa (a Brazilian payments startup), I led the re-architecture of our transaction-processing pipeline from a monolith to event-driven microservices, which reduced average payment latency by 40% and improved fault isolation so we could deploy independent services without affecting uptime. At a previous role supporting a large e-commerce client, I implemented database partitioning and optimized queries to cut peak-hour DB CPU usage by 35%, and introduced end-to-end tracing (OpenTelemetry) that helped decrease mean time to resolution for incidents by 50%. I am comfortable with CI/CD best practices (GitHub Actions, Jenkins), automated testing, and writing clear operational runbooks.

Nubank's focus on customer-centric simplicity, data-informed product development, and financial inclusion strongly resonates with my career goals. I am particularly inspired by how Nubank uses engineering to remove friction from everyday banking and to scale secure services for millions of customers. My experience building resilient, high-throughput systems and my attention to observability and security would allow me to contribute to core services—helping to maintain low-latency transactions, improve reliability during growth, and accelerate new feature delivery while maintaining regulatory and compliance standards.

I would welcome the opportunity to discuss how my technical skills and fintech experience can support Nubank's engineering goals. Thank you for considering my application; I look forward to the possibility of contributing to your backend platform and helping deliver exceptional products to customers across Brazil and beyond.

Sincerely,
Carlos Silva