Senior Staff Systems Engineer - Performance Engineer - JVM
Nubank
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Benefits offered by this job
Job summary
Nubank in the United States is seeking a Senior Systems Performance Engineer to lead deep-dive investigations into a large JVM-based microservices platform. You will identify systemic bottlenecks, tune GC and memory management, and build observability tooling to reduce latency and costs.
In a hybrid work model (2–3 days on site) across Palo Alto, Miami, Washington DC, Durham, you will mentor others, collaborate with the Computing Squad, and drive scalable infrastructure improvements for
Qualifications
- Expertise in JVM internals: deep, low-level knowledge of the JVM, including JIT (C1/C2), class loading, intrinsic methods.
- GC tuning: extensive experience with ZGC, G1, Shenandoah and tuning for large heaps and ultra-low latency.
- OpenJDK contribution is a plus.
- Linux kernel scheduling: understanding the Linux Scheduler (CFS/EEVDF) and high-concurrency Java workloads.
- Memory architecture: mastery of heap and off-heap memory, Direct Buffers and memory-mapped files.
- Advanced diagnostics: flamegraphs, JFR, eBPF, heap-dump analysis.
- CGroups and CPU throttling in Kubernetes/EKS.
- Concurrency: diagnose and resolve complex race conditions and lock contentions.
- Cloud: knowledge of AWS performance characteristics.
- Develops and delivers medium/long-term impact solutions.
- Understand system capabilities and limitations; contribute to improvements.
- Anticipate issues and mentor others.
Responsibilities
- Lead deep-dive performance investigations across a JVM-based microservices architecture.
- Tune JVM parameters and GC for reduced latency and infrastructure costs.
- Develop and implement observability tooling using eBPF, JFR, and Flamegraphs.
- Bridge Linux kernel and JVM alignment, optimize thread scheduling and resource isolation in Kubernetes.
- Architect scalable infrastructure improvements addressing long-term performance challenges.
- Mentor engineers and promote a culture of technical excellence and quality.
- Root-cause analysis of complex concurrency issues and memory leaks.
- Collaborate with the Computing Squad to align orchestration with performance goals.
Skills
Tools
Job description
Nu is the leading digital bank in Latin America, serving 135 million customers across Brazil, Mexico, and Colombia. The company has been leading an industry transformation by leveraging data and proprietary technology to develop innovative products and services.
Guided by its mission to fight complexity and empower people, Nu caters to customers’ complete financial journey, promoting financial access and advancement with responsible lending and transparency. The company is powered by an efficient and scalable business model that combines low cost to serve with growing returns.
Nu’s impact has been recognized in multiple awards, including Time 100 Most Influential Companies, Fast Company’s Most Innovative Companies, and Forbes World’s Best Banks. Visit our institutional page: https://www.nu.com/2026-en
The Systems Performance team is part of the Computing Squad consists of two distinct workstreams —Orchestration and System Performance —each with its own approach and challenges on managing and improving the foundational infrastructure where the majority of the Nubank's workloads runs.
The Performance team is focused on building deep diagnostic tools and performing high-level analysis to reduce latency, infrastructure costs and increase services efficiency.
You will be responsible for leading complex performance investigations, identifying systemic bottlenecks, and driving efficiency across one of the largest JVM-based microservice architectures in the world.
Our core principles and behaviors include ownership, simplicity, veracity-first, teamwork, and a focus on quality over quantity. During a normal work day, you will interact with critical infrastructure layers, from the Linux Kernel and JVM internals to cloud-wide orchestration.
- Leading Deep-Dive Investigations: Conduct high-level performance analysis to identify and resolve systemic bottlenecks across our global JVM-based microservices architecture.
- Optimizing Resource Efficiency: Drive initiatives to reduce infrastructure costs and latency by fine-tuning JVM parameters, Garbage Collection (ZGC, G1), and memory management (heap and off-heap).
- Building Diagnostic Tooling: Develop and implement advanced observability tools using eBPF, JFR, and Flamegraphs to provide real-time insights into kernel and runtime behavior.
- Kernel & Runtime Alignment: Bridge the gap between the Linux Kernel and the JVM, optimizing thread scheduling (CFS/EEVDF) and managing resource isolation (cgroups/throttling) within our Kubernetes environment.
- Architecting Scalable Solutions: Design and deliver innovative infrastructure improvements that address long‑term performance challenges, ensuring our systems scale ahead of demand.
- Technical Mentorship & Culture: Share expertise on JVM internals and performance best practices with the wider Engineering team, fostering a culture of technical excellence and "quality over quantity."
- Root Cause Excellence: Deep dive into complex concurrency issues, lock contentions, and memory leaks, providing definitive fixes for high‑impact technical debt.
- Strategic Collaboration: Work closely with the Computing Squad to align orchestration strategies with system performance goals, ensuring a seamless interface between infrastructure and workloads.
- Expertise in JVM Internals: Deep, low‑level knowledge of the JVM is essential. You must understand how the JVM works "under the hood," including JIT compilation (C1/C2), class loading, and intrinsic methods.
- JVM Tuning & Garbage Collection: Extensive experience with GC algorithms (ZGC, G1, Shenandoah), including the ability to tune them for massive heaps and ultra‑low latency requirements.
- OpenJDK Contribution (Major Plus): Previous experience contributing to the OpenJDK project or other low‑level runtime environments is a significant advantage.
- Linux Kernel & Scheduling: Deep understanding of the Linux Scheduler (CFS/EEVDF), thread scheduling, and how the kernel manages high‑concurrency Java workloads.
- Memory Architecture: Mastery of heap and off‑heap memory management, including Direct Buffers, memory‑mapped files, and diagnosing complex memory leaks.
- Advanced Diagnostics: Mastery of diagnostic tools such as Flamegraphs, JFR (Java Flight Recorder), eBPF, and performing large‑scale heap dump analysis.
- Resource Isolation: Extensive experience with cgroups and the impact of CPU Throttling on JVM quotas within Kubernetes/EKS.
- Concurrency: Proven ability to diagnose and resolve complex concurrency problems, including lock contention and race conditions at the instruction level.
- Cloud Platforms: Knowledge of AWS infrastructure and its performance characteristics.
- Develops and delivers innovative solutions that address team‑level or project‑level challenges, focusing on medium and long‑term impact
- Understand the technical aspects, capabilities, and limitations of our systems, contributing to discussions and improvements.
- Anticipate technical and product issues, making appropriate design decisions to avoid them
- Is enthusiastic about sharing knowledge and mentoring others.
- Deep dive into a problem to identify root causes when prioritized.
- Opportunity of earning equity at Nu
- Medical Insurance
- Dental and Vision Insurance
- Life Insurance and AD&D
- Extended maternity and paternity leaves
- Nucleo - Our learning platform of courses
- NuLanguage - Our language learning program
- NuCare - Our mental health and wellness assistance program
- Extended maternity and paternity leaves
- 401K
- Saving Plans - Health Saving Account and Flexible Spending Account
- Work-from-home Allowance
- Relocation Assistance Package, if applicable.
- Palo Alto, United States
- Miami, United States
- Washington DC, United States
- Durham, United States
Hybrid 2-3 times/week: Our hybrid work model brings us to the office at least twice a week, on strategic days designed to maximize team connection and collaboration. For more details, visit https://building.nubank.com/nu-hybrid-work-model/
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