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Senior Software Engineer, Backend (Consumer Authentication Platform)

Affirm· Checkout
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RemoteCA$153k - CA$213kfull-timePosted 3w ago

About the role

Senior backend engineer to design, build, and operate secure, scalable authentication platform capabilities that support sign-in, account recovery, step-up authentication, session management, identity federation, and related security and regulatory requirements across products, merchants, and geographies.

Responsibilities

  • Own the technical design and delivery of significant authentication platform capabilities, leading projects from early requirements and architecture through implementation, rollout, and ongoing operation.
  • Build secure, highly available systems that support consumer sign-in, authentication factors, account recovery, step-up authentication, session management, authorization, and identity federation.
  • Collaborate with product management, Security, Fraud, Compliance, design, and analytics; participate in ideation; articulate technical constraints; and partner on risk-aware decisions.
  • Translate security, regulatory, fraud, and customer-experience requirements into pragmatic technical designs balancing risk, friction, complexity, and delivery speed.
  • Proactively identify project, process, technology, security, reliability, or business issues; advocate for and lead in solving them.
  • Support operations and availability of team artifacts by creating and monitoring metrics, escalating when needed, and supporting on-call efforts.
  • Foster a culture of quality, security, and ownership by setting or improving code review and design standards and advocating beyond the team.
  • Develop talent on the team via mentoring, reviews, and hands-on collaboration; lead by example.
  • Communicate technical decisions, constraints, risks, and trade-offs to engineering and non-engineering audiences; lead investigation and resolution of complex production issues and identify systemic improvements.

Qualifications

  • 4+ years of experience designing, developing, and launching backend systems at scale using Python, Kotlin, Java, or another modern language.
  • Track record of developing highly available distributed systems using AWS, MySQL, Kubernetes, relational databases, event-driven architectures, and RPC or API frameworks.
  • Experience defining a technical plan for delivering a significant feature or system component with an elegant, secure, simple, extensible design; high-quality code.
  • Ability to make significant changes in a large codebase and implement testing strategies, migration plans, and controlled rollouts.
  • Demonstrated ownership of growth, seeking feedback, and mentoring other engineers.
  • Strong verbal and written communication skills for collaboration with global teams and cross-functional partners.
  • Equivalent practical experience or bachelor’s degree in a related field.
  • Familiarity with OAuth 2.0, OpenID Connect, WebAuthn/passkeys, FIDO2, JWTs, public-key cryptography; knowledge of NIST Digital Identity Guidelines or PCI DSS.
  • Experience designing session-management, token-issuance, account-recovery, or MFA systems; familiarity with risk-based or adaptive authentication and the interaction between identity, security, compliance, and fraud controls.

Skills

Required:Backend design and architectureDistributed systemsSecurity and complianceCommunication and collaboration

Benefits

  • Health coverage at no cost for employees and dependents.
  • Monthly stipends for tech setup and health/wellness options.
  • Flexible time off and generous holiday calendar.
  • Employee stock purchase plan (ESPP) with stock at a discount.
Last updated Sep 30, 2026. Interested? Apply on the company site.

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