Staff Application Security Engineer

Why join us

Brex is the intelligent finance platform that enables companies to spend smarter and move faster in more than 200 markets. By combining global corporate cards and banking with intuitive spend management, bill pay, and travel software, Brex enables founders and finance teams to accelerate operations, gain real-time visibility, and control spend effortlessly. Brex’s AI-native automation and world-class service eliminate manual expense and accounting tasks for customers so they can focus on what matters most. Tens of thousands of the world's best companies run on Brex, including DoorDash, Coinbase, Robinhood, Zoom, Plaid, Reddit, and SeatGeek.

Working at Brex allows you to push your limits, challenge the status quo, and collaborate with some of the brightest minds in the industry. We’re committed to building a diverse team and inclusive culture and believe your potential should only be limited by how big you can dream. We make this a reality by empowering you with the tools, resources, and support you need to grow your career.

Engineering at Brex

Engineering at Brex is about building systems that scale with speed and intention. Our teams span Software, Data, Security, and IT, and operate with high autonomy and deep collaboration. We tackle hard technical problems, own our outcomes, and push for excellence at every level — from architecture to deployment. It’s an environment where engineering is a craft, and builders become leaders.

Responsibilities:

Lead the technical vision and strategic roadmap for the Application Security team, aligning security objectives with Brex's enterprise growth and high-velocity engineering metrics.

Establish technical standards and secure defaults across the entire engineering organization, fostering a culture of collaborative security excellence and bridging product platforms, infra, and trust.

Architect and secure novel AI/ML and agentic workflows, applying cutting-edge practices to mitigate risks such as prompt injection, model manipulation, and data poisoning.

Mentor and coach engineers within the team and across the broader organization, guiding technical growth, helping individuals level up their security expertise, and accelerating team delivery.

Drive proactive vulnerability discovery and offensive security testing strategies, executing complex attack chains to demonstrate business impact and prioritize cross-functional remediation.

Partner with Product Platform, Cloud Infrastructure, and Data engineering teams to ensure core primitives, APIs, and microservices are secure by default from design to deployment.

Requirements:

8+ years of experience in Application Security, Product Security, or software engineering with a primary focus on offensive and defensive application security.

Proven track record of technical leadership and team mentorship on complex, multi-quarter security engineering initiatives in a fast-paced environment.

Deep proficiency and technical expertise in AI security, including hands-on experience securing agentic architectures, LLM gateways, and evaluating adversarial AI vectors.

Strong systems-thinking capabilities with extensive experience defining secure product development lifecycles, threat modeling complex topologies, and cloud-native container security (AWS, Kubernetes).

Proficiency in Python, Go, or similar languages to architect internal tooling, pipeline automation, and advanced detection/scanning engines.

Exceptional written and verbal communication skills, with a demonstrated ability to navigate ambiguity, influence technical leaders, and manage up and out across EPD organizations.

Bonus Points:

Experience with Kotlin, gRPC, GraphQL, Kubernetes

Previous experience in building and scaling security teams

Experience with securing distributed systems in AWS and cloud environments

Contributions to the wider technical community — open source, public research, CTF participation, blogging, CVEs, or presentations