Security Engineer, Cardless

• Strong programming skills in Java, Python, or a comparable language — you write production code
• Experience designing or operating secure platform / B2B APIs at scale, especially in multi-tenant environments
• Background in anti-ATO, anti-fraud, or authentication systems at scale (consumer fintech, marketplace, or large consumer platform)
• Working knowledge of AWS: IAM, KMS, networking, service-to-service auth
• Comfort with modern AI tooling (Claude, Copilot, and similar) as a daily force multiplier across code review, threat modeling, detection engineering, and security tooling
• Excellent written communication. You'll write threat models, postmortems, and partner-facing security responses
• Comfortable owning the security function in-house while leveraging external specialists as a force multiplier

Desirable

• We're hiring a Product Security Lead to drive how we build security into the platform
• The work spans authentication, authorization, anti-abuse controls, in-product fraud primitives, and the secure-by-design practices that come with running credit infrastructure for partners of this caliber
• The role is hands-on and deeply cross-functional, working with Engineering, Risk, Compliance, Legal, and Data
• You'll report to the Head of Engineering
• Own the security model for our partner-facing APIs: authentication, authorization, tenant isolation, abuse prevention, signing, and audit logging
• Drive a coherent auth strategy across services and surfaces, including step-up auth for sensitive actions and a strong-auth roadmap (passkeys and beyond)
• Build the device telemetry, behavioral signals, and velocity primitives that fraud and risk functions depend on
• Be the secure-by-design partner with Engineering — sit in on architecture reviews before features ship, write the threat models, own the tradeoffs
• Own secure SDLC: SAST/DAST, dependency scanning, secret detection, and the security tooling engineers interact with daily
• Coordinate with our infrastructure team to improve our security posture across the stack: from infrastructure, to supply chain, to first-party applications, to third-party dependencies and SaaS platforms
• Be the technical authority on sensitive payment data. Keep the footprint small and well-defined as the platform grows
• Lead incident response on security events (containment, forensics, comms, blameless postmortems) and drive vulnerability remediation across services
• Own the relationship with our external security architecture partner: set priorities, scope engagements, integrate findings into our roadmap
• Serve as the technical counterpart to ensure compliance, translating SOC 2, PCI DSS, and other security frameworks into scalable engineering solutions and ensuring in-product controls are effective in practice - not just on paper
• You'll lead product security for a platform that powers some of the most recognizable card programs in the world. The work moves real dollars and real trust from the moment you ship. You'll have a real seat in every major architecture conversation, executive visibility, and an external security architecture partner you can lean on