Cardless

Security Engineer - Product

Cardless$190K — $260K *
Finance & Insurance
Less than 5 years of experience
Job Overview by Ladders

Qualifications

  • Strong programming skills in Java, Python, or similar language, with a focus on writing production code.
  • Experience designing or operating secure platforms/B2B APIs at scale, particularly in multi-tenant contexts.
  • Background in antifraud systems or authentication for consumer fintech or large platforms.
  • Working knowledge of AWS services, including IAM and KMS, and service-to-service authentication.
  • Familiarity with modern AI tools to enhance security processes and code quality.
  • Excellent written communication skills for creating documents like threat models and security responses.
  • Ability to manage an in-house security function while collaborating with external experts.

Responsibilities

  • Own the security model for partner-facing APIs, covering various access and abuse prevention techniques.
  • Develop a coherent authentication strategy, including advanced authentication methods for sensitive actions.
  • Implement device telemetry and behavioral signals essential for fraud prevention and risk management.
  • Collaborate with Engineering to ensure security is integrated into architecture before feature launch, through threat models and tradeoff ownership.
  • Manage secure SDLC processes, including SAST/DAST and security tooling for engineering teams.
  • Work with infrastructure teams to enhance overall security from infrastructure to dependencies.
  • Lead incident response for security events, ensuring effective containment and remediation of vulnerabilities.

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
Full Job Description
We9re 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. You9ll 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. You9ll 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.
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
  • 69b 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.

About Cardless

Cardless is a financial technology company that offers a mobile payment platform for merchants. The company was founded in 2014 by Michael Spelfogel and Jonno Rodd. Cardless has offices in San Francisco, California and Sydney, Australia. The company's mission is to make payments faster, easier, and more secure for everyone.
Learn more about Cardless
Size
50 employees
Industry
Net Income
-$500,000
Founded
2014
5 Year Trend
+250%
Revenue
$1 million

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