Security Engineer II (Defensive Operations)

Flywire•Boston, MA

8d•Hybrid

About The Position

At Flywire, we are looking for a Security Engineer II to join our global Security Engineering team. In this role, you will serve as a technical authority owning secure software design, cloud-native infrastructure defense, offensive penetration testing, and real-time incident detection across Flywire’s global footprint. You will combine a "breaker" mindset with a builder’s engineering empathy, operating fluidly across the entire product and infrastructure security lifecycle. This role demands an "automation-first" approach embedded within a high-velocity fintech ecosystem. You will actively partner with software engineering and SRE squads to integrate security controls directly into our public cloud and GitLab CI/CD pipelines using AI workflows. Simultaneously, you will serve as an operational responder for threat detection engineering, red team penetration testing, and live incident containment.

Requirements

Bachelor’s degree in Computer Science, Cyber Security, Software Engineering, or a related technical discipline (or equivalent experience).
3+ years of progressive engineering experience moving fluidly between Application Security, Cloud Architecture Defense, and Active Security Operations (SecOps/Incident Response/Penetration Testing).
Proven track record of independently performing deep manual penetration testing, web application exploitation, and incident containment without relying solely on commercial automated scanners.
Strong practical knowledge of AWS or public cloud topologies, containerization (Docker, Kubernetes), network security, and building/maintaining GitLab CI pipelines.
Foundational proficiency with modern web development frameworks and programming languages including Python, Ruby on Rails, Java, or Node.js.
Solid understanding of the OWASP Top 10 for LLMs framework, applied cryptography, cloud network isolation, and federated authentication architectures (OAuth2, SAML, OIDC, Zero Trust IAM).
Working proficiency with modern EDR platforms, SIEM systems, network packet analysis (PCAP), threat intelligence frameworks (MITRE ATT&CK), and forensic collection tools.
Practical experience aligning technical software and infrastructure controls with standards like PCI-DSS (v4.0), SOC 1, SOC 2, or DORA.

Nice To Haves

Offensive/Red Team: OSCP, OSCE, or SANS GXPN.
Cloud & Architecture: AWS Certified Security - Specialty, CKS (Certified Kubernetes Security Specialist), or CISSP.
Incident Response: GCIH, GCFA, or specialized Blue Team certifications.
AI Security: OffSec OSAI.

Responsibilities

Own, design, and drive the end-to-end integration of automated technical security requirements and validation tools into high-velocity engineering pipelines.
Build custom internal tooling, wrappers, and automated controls to maximize development velocity without friction.
Partner directly with SRE and DevOps teams to establish secure cloud architecture blueprints, manage Infrastructure-as-Code (IaC) security scans (Terraform), and enforce Zero Trust boundaries in containerized environments (Docker/Kubernetes).
Design and deploy automated security review workflows using LLM APIs (e.g., Claude).
Establish controls to protect generative AI features against prompt injection, insecure output handling, model inversion, and data poisoning.
Adopt an attacker's mindset to discover logic flaws, perform exploit research, and emulate zero-day adversarial behavior across financial platforms through manual source code audits, API exploitation, and cloud penetration testing.
Lead technical containment, forensic collection, and rapid threat eradication during active security incidents.
Design and deploy high-fidelity detection rules and automated alert workflows within the SIEM environment.
Embed within software development and infrastructure sprint planning from inception to ensure security is built-in from day one.
Provide actionable code modifications and mentor junior engineers.