Senior Security Engineer (Blockchain Security)

Nubank; Rio de Janeiro; Hybrid; BRL 260,000 - 380,000; Full time

Benefits offered by this job

Equity eligibility

Meal card

Public transportation

Mental health program

Life Insurance

Medical Plan

Dental Plan

Language Course (NuLanguage)

Learning platform (Nucleo)

Extended Parental Leave

Daycare Allowance

Parental Consultancy

Work-from-home Allowance

Gym partnerships

30 days paid vacation

Relocation assistance

Job summary

Nubank is seeking a Senior Security Engineer to own the security posture of our crypto operations, shaping defenses and ensuring regulatory compliance. You will craft secure architectures, build in-house security tooling, and leverage AI-assisted methods to elevate threat modeling and vulnerability reviews.

You will collaborate with product and engineering teams, work in a hybrid model in Brazil, and contribute to an environment focused on protecting customer funds and scalable crypto products.

Qualifications

• Strong product security and/or offensive security background (penetration testing, vulnerability assessment, attack simulation, incident response).
• Experience embedding security into product development: threat modeling, secure SDLC, security-by-design reviews.
• Hands-on software engineering ability: build and operate security services and automation, not just use off-the-shelf tools; comfortable with production code (Clojure) and other modern languages.

Responsibilities

• Apply an offensive security mindset to crypto and blockchain products; simulate attacks and run security assessments.
• Drive product security across the crypto portfolio with threat modeling and secure-by-design reviews.
• Build and operate in-house security services and tooling: hardened ingress, monitoring, secret-management, automated security-review tooling.
• Ensure crypto operation meets regulatory requirements; map controls to regulations and support audits.
• Collaborate with product and engineering to design secure blockchain architectures and embed security-by-design.
• Contribute to security policies, standards, and guidelines for blockchain security operations.
• Leverage AI-assisted tooling for threat modeling, code review, and attack simulations; continuously improve AI-first security practices.

Skills

Offensive security

Threat modeling

Secure SDLC

Production coding (Clojure)

Blockchain basics

AWS

English communication

Incident response

Tools

CI/CD security tools

Secret management

Monitoring tooling

Threat modeling tools

Cloud infrastructure (AWS)

Job description

About Nu

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.

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

About The Role

The Blockchain Security team sits within the Product Security & Assurance BA, part of the Information Technology and Security (ITSec) BU. Our mission is to support the security of Nu's crypto operation. In the context of Nu's global expansion, keeping these products secure, and demonstrably compliant with financial regulators, is a direct condition for our ability to operate and grow.

As a Senior Security Engineer on this team, you own the security posture of our crypto operation. You are the person who thinks like an attacker so our products can withstand real ones: finding vulnerabilities before adversaries do, embedding product security into how crypto products are designed and built, and making sure our controls satisfy both internal risk standards and external regulatory requirements. You won't just run security tools. You'll build and operate the ones that protect our crypto products, from hardened ingress and monitoring/alerting systems to secure secret-management and automated security-review tooling. Your work directly protects customer funds and Nu's ability to run crypto products at scale.

You’ll be responsible for

• Applying an offensive security mindset to our crypto and blockchain products: simulating attacks, running penetration tests and security assessments, and turning findings into concrete mitigations.
• Driving product security across the crypto portfolio: threat modeling, security-by-design reviews, and embedding secure practices into the development lifecycle.
• Building, operating, and improving in-house security services and tooling that integrate directly with our crypto products, for example hardened ingress/edge controls, security monitoring and anomaly alerting, secure secret-management, and automated security-review tooling.
• Ensuring our crypto operation meets regulatory requirements: mapping controls to applicable regulations, supporting audits, and producing the evidence regulators and internal risk teams expect.
• Collaborating with product and engineering teams to design secure blockchain architecture and embed security-by-design into new products.
• Contributing to security policies, standards, and guidelines that govern blockchain security operations.
• Using AI to raise the leverage and quality of security work: building and running AI‑assisted tooling for tasks like threat modeling, code and vulnerability review, and attack simulation, and helping the team push the frontier of what AI‑first security engineering looks like.
• Staying current on emerging attack vectors, exploits, and best practices across product and blockchain security, and sharing that knowledge across the team.

We Are Looking For a Person Who Has

Must have

• Strong product security and/or offensive security background (penetration testing, vulnerability assessment, attack simulation, incident response).
• Experience embedding security into product development: threat modeling, secure SDLC, security‑by‑design reviews.
• Hands‑on software engineering ability: you can build and operate security services and automation, not just use off‑the‑shelf tools. Comfortable writing production code (we work heavily in Clojure; strong experience in any modern language plus willingness to learn Clojure is fine).
• Solid working knowledge of blockchain and cryptocurrency fundamentals, including how blockchains, wallets, keys, and smart contracts work, enough to reason about their security (expert‑level depth not required, but real familiarity is).
• Strong knowledge of recent and past attack vectors and exploits, and how to remediate them.
• Experience with security frameworks such as OWASP and the NIST Cybersecurity Framework (CSF).
• Fluency with AI‑assisted engineering: using coding agents and LLMs in daily work, with good judgment about where they help, where they don't, and how to review their output critically.
• Familiarity with AWS, and solid grounding in operating systems, networks, databases, and infrastructure architecture.
• Ability to work autonomously and proactively, strong analytical/problem‑solving skills, and clear written and spoken English for technical and non‑technical audiences.

Nice to have

• Deeper knowledge of blockchain/crypto internals: consensus algorithms, cryptographic protocols, smart contracts.
• Experience auditing smart contracts (e.g. Solidity) or working with DeFi protocols.
• Experience integrating with third‑party crypto custody/infrastructure providers (e.g. Fireblocks, Circle, and similar).
• Exposure to regulatory or compliance requirements in a financial or crypto context.
• Experience with bug bounties and/or CTFs.
• Certifications such as OSCP, OSWE, or Certified Blockchain Security Professional.

Location for this opportunity

• São Paulo, Brazil
• Campinas, Brazil
• Rio de Janeiro, Brazil
• Belo Horizonte, Brazil

Our Benefits

• Chance of earning equity at Nubank
• Food/ Meal Card (Vale-Refeição and/or Vale Alimentação)
• Public Transportation Commuting Benefit (Vale-Transporte)
• NuCare – Psychological, Financial and Legal Assistance Program
• Life Insurance
• Medical Plan
• Dental Plan
• NuLanguage – Language Course Program
• Nucleo - Our learning platform of courses
• Extended Parental Leave
• Daycare Allowance
• Parental Consultancy
• Work-from-home Allowance
• Gym Partnerships
• 30 days of paid vacation
• Relocation Assistance Package, if applicable

Work Model for this Role

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/

Our recruitment process may involve the use of artificial intelligence‑enabled tools, such as automated interview transcription and analysis, to support the evaluation process. Artificial intelligence is not used to make final hiring decisions; all decisions are made by human reviewers.