Senior Software Engineer, Backend (AI Platform)

Role overview

Responsibilities

• Own technical decisions and projects from design through launch and on-call.
• Build scalable gateways, runtimes, and evaluation services for production AI workloads.
• Develop identity, quota, routing, caching, and failover controls for AI usage.
• Partner across security, infrastructure, and product engineering to establish agent guardrails and tool-access identity.
• Own metrics and operational health, including monitoring, alerting, runbooks, and on-call.
• Set and promote code review and design standards; use AI tools and agentic workflows in daily engineering.
• Mentor engineers and promote strong design, coding, and testing practices.

Qualifications

• At least 4 years designing, developing, and launching scalable backend systems using languages such as Python or Kotlin.
• Experience with highly available distributed systems and technologies such as AWS, MySQL, and Kubernetes.
• Production experience with LLMs, agents, or AI frameworks, including areas such as inference APIs, gateways, MCP, tool calling, evaluations, or agent runtimes.
• Understanding of AI workloads and the infrastructure needed to support them.
• Experience planning and delivering significant features or system components with extensible design and high-quality code.
• Proficiency safely making significant changes in a large codebase.
• Strong written and verbal communication skills for global engineering collaboration.
• Equivalent practical experience or a bachelor’s degree in a related field.

Workplace

• This is a remote role open to candidates residing in Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, or Saskatchewan.
• Affirm is remote-first; some roles may occasionally require office attendance, and new hires are invited to in-person onboarding.

Compensation

• Canadian base pay range is CAD 153,000–213,000 per year.
• Total compensation may include equity, monthly spending stipends, and benefits.

Benefits

• Health coverage includes subsidized medical, dental, and vision premiums for employees and dependents.
• Monthly stipends support technology, health, and wellness spending.
• Flexible time off, holiday calendars, and an employee stock purchase plan are offered.