Staff Product Security Engineer

Affirm is reinventing credit by providing consumers with flexible buy-now-pay-later options without hidden fees or compounding interest. The Staff Product Security Engineer will design, build, and operate core customer identity and access management backend services for registration, authentication, authorization, account lifecycle, and profile management across B2C and B2B platforms. The role also involves implementing identity standards, integrating CIAM platforms, automating infrastructure, and ensuring secure, reliable, high-scale operations.

Responsibilities:

• Design, build, and operate core CIAM backend services that support customer registration, authentication, authorization, account lifecycle, and profile management for B2C and B2B platforms
• Implement and extend identity standards such as OAuth 2.0, OIDC, SAML, and SCIM in code, ensuring correctness, scalability, and clean integration patterns
• Develop backend APIs and services in Python and Kotlin that expose identity capabilities to web, mobile, and partner applications
• Integrate CIAM platforms with internal systems, including user data stores, messaging, fraud signals, and downstream customer platforms
• Own secure authentication and account flows end to end, including MFA, step-up authentication, device binding, consent, and adaptive authentication logic
• Automate CIAM infrastructure and deployments using Infrastructure as Code and CI/CD pipelines, treating identity as a core platform service
• Monitor, debug, and optimize CIAM services for performance, resilience, and abuse detection in high-scale environments

Requirements:

• 7+ years of experience designing, developing and launching backend systems at scale using languages like Python or Kotlin
• Extensive track record of developing highly available distributed systems using technologies like AWS, MySQL, Spark and Kubernetes
• Strong verbal and written communication skills that support effective collaboration with our global engineering team
• Experience delivering major features, system components or deprecating existing functionality in a system through the definition of a technical and execution plan
• Write high quality code that is easily understood and used by others
• Design, build, and operate core CIAM backend services that support customer registration, authentication, authorization, account lifecycle, and profile management for B2C and B2B platforms
• Implement and extend identity standards such as OAuth 2.0, OIDC, SAML, and SCIM in code, ensuring correctness, scalability, and clean integration patterns
• Develop backend APIs and services in Python and Kotlin that expose identity capabilities to web, mobile, and partner applications
• Integrate CIAM platforms with internal systems, including user data stores, messaging, fraud signals, and downstream customer platforms
• Own secure authentication and account flows end to end, including MFA, step-up authentication, device binding, consent, and adaptive authentication logic
• Automate CIAM infrastructure and deployments using Infrastructure as Code and CI/CD pipelines, treating identity as a core platform service
• Monitor, debug, and optimize CIAM services for performance, resilience, and abuse detection in high-scale environments
• Strong experience designing and implementing CIAM systems, with deep, hands-on knowledge of OAuth 2.0, OIDC, SAML, and SCIM beyond basic configuration
• 5+ years of professional backend software engineering experience
• Strong production experience in Python or a similar backend language
• Experience designing APIs, automation frameworks, and distributed systems
• Hands-on experience building and maintaining CI/CD pipelines
• Experience with GitHub-based development workflows and Buildkite or similar build systems
• Experience with cloud-native development, preferably AWS
• Hands-on experience extending and integrating CIAM platforms such as Okta, Auth0, Ping Identity, ForgeRock, or Azure AD B2C using custom code, hooks, and APIs
• Solid understanding of backend and distributed systems fundamentals, including API design, data modeling, latency, error handling, and observability
• Experience with Infrastructure as Code and automation tools such as Terraform, plus CI/CD pipelines for deploying backend services
• Strong security fundamentals applied through engineering, including access control models, token handling, encryption, MFA, and privacy by design
• Clear communication skills and the ability to work closely with product, frontend, mobile, and security teams while owning backend identity services
• Familiarity with tools such as Cursor and other AI-augmented development environments