Senior Security Engineer — Build Secure Fintech Systems

Flex; Northern (KY); Hybrid; USD 170,000 - 230,000; Full time

Job summary

Flex is building an AI-native private bank for business owners, offering secure money movement and financial services at scale. We are hiring our first security engineers to own product and infrastructure security, reporting to the CTO.

You will create automated checks, guardrails, and secure defaults across money-transfer systems, card issuance, payouts, and the stablecoin work, with emphasis on speed and ownership.

Qualifications

• Substantial hands-on software engineering experience with a security focus.
• Experience in threat modeling and identifying risk in distributed systems.
• Proficiency with cloud platforms (AWS or GCP) and IaC tools (Terraform).
• Knowledge of secret management, workload identity, and service-to-service authorization.
• Familiarity with CI/CD pipelines, security automation, and secure defaults.
• Experience at fintech or payments or regulated environments is a plus.

Responsibilities

• Design and implement secure-by-default infrastructure and guardrails across services.
• Build automation for vulnerability detection, SBOM hygiene, and secure software development lifecycle checks.
• Lead risk decisions and triage vulnerabilities with an end-to-end security program.
• Partner with Engineering, IT, Risk, and Compliance on security reviews and audits.
• Drive security automation, including AI-assisted triage and review.
• Manage external penetration testing and bug-bounty coordination when applicable.
• Develop golden paths to prevent sensitive data from appearing in logs.

Skills

Security engineering

Software engineering

Threat modeling

Cloud security

Python

Go

TypeScript

CI/CD

Security tooling

Tools

AWS

GCP

Terraform

Kubernetes

CI/CD tooling

Job description

Flex is building an AI-native private bank for business owners, offering secure money movement and financial services at scale. We are hiring our first security engineers to own product and infrastructure security, reporting to the CTO.

You will create automated checks, guardrails, and secure defaults across money-transfer systems, card issuance, payouts, and the stablecoin work, with emphasis on speed and ownership.