Security Engineer

Overview

This position is based in our San Francisco or New York office

Modern Treasury’s mission is to build the most trusted financial infrastructure for global money movement. We’re looking for a Security Engineer to design and strengthen the controls that protect our payment infrastructure. You’ll enable teams to build secure, compliant financial products without slowing down development.

Modern Treasury is expanding deeper into money movement. We’re building new products that will let customers move funds across both traditional rails and emerging technologies, including stablecoins. You’ll help design and operate the security controls that make this possible and set the foundation for compliant, programmable money movement at scale.

About The Role

This role sits at the intersection of security, infrastructure, platform, and payments engineering. You’ll shape how Modern Treasury manages risk at scale and design the systems that make programmatic, compliant money movement possible. Your work will ensure that as we grow into new products and rails, we continue to move fast while keeping trust, compliance, and safety at the core of our platform.

What You’Ll Do

• Strengthen the security foundation of Modern Treasury’s payments infrastructure to protect money movement at scale
• Help reduce fraud, prevent abuse, and safeguard customer data as we expand into new rails and stablecoins
• Shape how engineering teams build secure, compliant products without slowing down development
• Design automation, monitoring, and remediation practices that keep our systems resilient and trustworthy
• Influence the future of financial infrastructure by embedding strong security practices into our systems and culture

What You Should Have

Required Experience

• 7+ years of security engineering experience, including 2+ years in the payments industry
• Hands-on expertise with AWS security services
• Strong background reviewing and securing full stack application code (frontend, backend, and APIs)
• Frontend security knowledge (JavaScript, modern web frameworks, browser security models)
• Proficiency in secure API design, authentication and authorization, applied encryption, and PCI DSS compliance
• Experience with infrastructure as code (Terraform) and CI/CD security (SAST/DAST scanning)
• Payments experience, ideally including fraud prevention, NACHA rules, and risk controls in money movement systems
• What Sets You Apart
• Deep understanding of payment processing security across ACH, wires, card networks, and emerging rails
• Experience building controls for fraud detection, chargeback prevention, and abuse mitigation in payments systems
• Familiarity with NACHA operating rules and regulatory standards for money movement
• Proven experience securing high-throughput systems (>10K TPS) and multi-tenant architectures
• Knowledge of application security for Ruby on Rails, GraphQL, and containerized environments
• Familiarity with SIEM tools, vulnerability scanning, and incident response procedures
• Track record of balancing strong security requirements with engineering velocity
• Clear communication skills to collaborate across Product, Platform, Infrastructure, and Compliance teams
• Data-driven approach to prioritizing security investments and mitigating risk

Technologies We Use

• Ruby on Rails for our backend framework
• React, GraphQL, and Tailwind CSS on the front end
• Postgres for our database
• AWS for infrastructure and hosting

• Docker For Containerization

• GitHub for source code management
• Buildkite for continuous integration
• Reg tech and anti-fraud platforms

About Modern Treasury

Modern Treasury is the operating system for money movement. Our payments platform combines a suite of APIs and dashboards to help companies unlock new payments revenue, strengthen customer experiences, and drive efficiency through their business. Our end-to-end platform moves enterprises forward with faster payments, efficient workflows, full data visibility.

Modern Treasury is committed to equal employment opportunity and does not discriminate in any employment opportunities or practices based on an individual's race, color, creed, gender (including gender identity and gender expression), religion (all aspects of religious beliefs, observance or practice, including religious dress or grooming practices), marital status, registered domestic partner status, age, national origin or ancestry (including language use restrictions and possession of a driver’s license issued under California Vehicle Code section 12801.9), natural hair, physical or mental disability, political affiliation, medical condition (including cancer or a record or history of cancer, and genetic characteristics), sex (including pregnancy, childbirth, breastfeeding or related medical condition), genetic information, sexual orientation, military and veteran status or any other consideration made unlawful by federal, state, or local laws. It also prohibits unlawful discrimination based on the perception that anyone has any of those characteristics, or is associated with a person who has or is perceived as having any of those characteristics.

Modern Treasury participates in E-Verify and will provide the federal government with your Form I-9 information to confirm that you are authorized to work in the U.S.