Senior Staff Systems Engineer - Performance Engineer (JVM)

TL;DR

Senior Staff Systems Engineer (JVM): Leading complex performance investigations to identify systemic bottlenecks and drive efficiency across one of the world's largest JVM-based microservice architectures. With an accent on JVM internals, garbage collection, and Linux kernel optimization. Focus on building deep diagnostic tools, resolving complex concurrency issues, and architecting scalable infrastructure solutions.

Location: Hybrid 2-3 times/week in Palo Alto, Miami, Washington DC, or Durham, United States.

Company

Nu is one of the largest digital financial platforms in the world, with more than 127 million customers across Brazil, Mexico, and Colombia, focused on redefining financial services.

What you will do

• Lead deep-dive performance investigations to identify and resolve systemic bottlenecks across the JVM-based microservices architecture.
• Optimize resource efficiency by fine-tuning JVM parameters, Garbage Collection (ZGC, G1), and memory management.
• Develop and implement advanced observability and diagnostic tools using eBPF, JFR, and Flamegraphs.
• Bridge the gap between the Linux Kernel and JVM, optimizing thread scheduling and managing resource isolation within Kubernetes.
• Design and deliver innovative infrastructure improvements to address long-term performance challenges and ensure scalability.
• Provide technical mentorship on JVM internals and performance best practices, fostering a culture of technical excellence.

Requirements

• Deep, low-level knowledge of JVM Internals (JIT compilation, class loading, intrinsic methods).
• Extensive experience with JVM Tuning & Garbage Collection (ZGC, G1, Shenandoah) for massive heaps and ultra-low latency.
• Deep understanding of the Linux Kernel & Scheduler (CFS/EEVDF) and high-concurrency Java workloads.
• Mastery of heap and off-heap Memory Architecture, including diagnosing complex memory leaks.
• Expertise in advanced diagnostic tools like Flamegraphs, JFR, and eBPF, plus large-scale heap dump analysis.
• Extensive experience with resource isolation (cgroups) and CPU Throttling impact within Kubernetes/EKS.
• Proven ability to diagnose and resolve complex concurrency problems, lock contention, and race conditions.
• Knowledge of AWS infrastructure and its performance characteristics.

Nice to have

• Previous experience contributing to the OpenJDK project or other low-level runtime environments.

Culture & Benefits

• Opportunity to earn equity.
• Comprehensive medical, dental, vision, life, and AD&D insurance.
• Extended maternity and paternity leaves.
• Access to learning platforms (Nucleo) and language learning program (NuLanguage).
• Mental health and wellness assistance program (NuCare).
• 401K and Saving Plans (HSA, FSA).
• Work-from-home allowance and relocation assistance package (if applicable).
• Hybrid work model requiring office presence 2-3 times/week for team connection and collaboration.