Senior Software Engineer, Backend (Consumer Authentication Platform)

Location: Remote within Canada only; candidates must reside in Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, or Saskatchewan.

Base pay: CAD 153,000–213,000 per year, depending on location, experience, and job-related skills.

Company

Affirm provides transparent, predictable payment solutions that allow consumers to pay over time.

What you will do

• Own the technical design and delivery of significant authentication platform capabilities from requirements and architecture through rollout and ongoing operation.
• Build secure, highly available systems for sign-in, authentication factors, account recovery, step-up authentication, session management, authorization, and identity federation.
• Translate security, regulatory, fraud-prevention, and customer-experience requirements into pragmatic technical designs.
• Collaborate with Product, Security, Fraud, Compliance, Design, Analytics, and engineering teams on technical decisions, risks, and trade-offs.
• Monitor system health, support on-call operations, investigate complex production issues, and lead systemic reliability improvements.
• Improve engineering standards through design reviews, code reviews, technical writing, mentoring, and technical leadership.

Requirements

• 4+ years of experience designing, developing, and launching backend systems at scale using Python, Kotlin, Java, or a comparable modern programming language.
• Experience with highly available distributed systems, AWS, MySQL, Kubernetes, relational databases, event-driven architectures, and RPC or API frameworks.
• Ability to design secure, simple, extensible systems and safely make significant changes in large codebases using testing, migration, and controlled rollout strategies.
• Familiarity with OAuth 2.0, OpenID Connect, WebAuthn/passkeys, FIDO2, JWTs, public-key cryptography, NIST Digital Identity Guidelines, or PCI DSS.
• Experience designing session management, token issuance, account recovery, or multi-factor authentication systems, including risk-based or adaptive authentication.
• Equivalent practical experience or a bachelor’s degree in a related field, plus strong written and verbal communication skills.

Culture & Benefits

• Remote-first work with flexibility within the country of employment; occasional in-person office work may be required, and new hires attend in-person onboarding.
• 100% employer-paid medical coverage for employees and dependents, including dental and vision benefits.
• Monthly stipends for technology, health, and wellness expenses.
• Flexible time off and generous holiday calendars.
• Employee stock purchase plan with a discount on Affirm stock.