Senior Staff Systems Engineer - Performance Engineer - JVM

ABOUT US

Nu is one of the largest digital financial platforms in the world, with more

than 127 million customers across Brazil, Mexico, and Colombia. Guided by our

mission to fight complexity and empower people, we are redefining financial

services in Latin America and this is still just the beginning of the purple

future we're building.

Listed on the New York Stock Exchange (NYSE: NU), we combine proprietary

technology, data intelligence, and an efficient operating model to deliver

financial products that are simple, accessible, and human.

Our impact has been recognized by global rankings such as Time 100 Companies,

Fast Company’s Most Innovative Companies, and Forbes World’s Best Bank. Visit

our institutional page https://international.nubank.com.br/careers/

About the Role

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.

YOU'LL BE RESPONSIBLE FOR

* 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.

WE ARE LOOKING FOR A PERSON WHO HAS

* 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.

Benefits

* 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.

Location for this opportunity (City, Country)

* Palo Alto, United States

* Miami, United States

* Washington DC, United States

* Durham, United States

WORK MODEL FOR THIS ROLE

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/

[https://building.nubank.com/nu-hybrid-work-model/]