Cardless is the infrastructure that lets consumer brands put credit cards directly in their own product. Instead of sending customers off to a bank's website to manage their card, our platform handles the credit program end-to-end (applications, underwriting, servicing, rewards, compliance), so brands can build the card experience inside their own ecosystem. We power programs for Coinbase, Bilt, Qatar Airways, Alibaba, and others. We've raised $170M to date, most recently a $60M Series C led by Spark Capital. 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. RESPONSIBILITIES * 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. WHAT WE LOOK FOR * 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. NICE TO HAVE * Fintech, payments, or other regulated environment experience. * Threat modeling methodology background (STRIDE, attack trees, or your own). * Experience working alongside or building for a risk / fraud operations team. * Experience operating a bug bounty or vulnerability disclosure program. WHY CARDLESS 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. BENEFITS * 💸 Meaningful start-up equity * 🏥 100% health, vision & dental primary coverage * ➕ 75% health, vision & dental dependent coverage * 🍱 Catered lunches and dinners * 🚎 $250/month commuter benefit * 👶 Parental leave * ✈️ Team building events * 🌴 Flexible PTO with a minimum of 15 days off per year * 💸 401(k) plan * 🚛 Relocation assistance COMPENSATION This role has an annual starting salary range of $190,000–$260,000 + equity + benefits (see above). Actual compensation is influenced by a wide array of factors including but not limited to skills, experience, and specific work location. LOCATION San Francisco, CA — our office is in the Jackson Square district. This role is 5 days a week in office.