Staff Software Engineer, Backend (Cost Engineering)

About the Position

At Affirm, we exist for the moments that matter-giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most.

Engineering owns cost visibility and optimization across Affirm's cloud and AI infrastructure. We're the team that tells the business what it's spending, why it's changing, and what to do about it - from AWS resource waste and tagging strategy to the newer frontier of AI/LLM spend across the company's growing set of AI tools. We treat cost anomalies with the same rigor as production incidents: we've built a severity framework (mirroring Affirm's SEV0–3 incident model but mapped to dollar impact) with defined detection sources, TTD/TTR metrics, and escalation paths, and we operate a clear RACI with partner orgs - we own visibility and alerting, and partner teams own remediation (at times we may dig in deep and own remediation too!), so accountability never gets diffuse.

As a Staff Cost Engineer, you'll operate at the intersection of finance, infrastructure, and data engineering - designing the tooling, automation, and processes that scale cost governance across a fast-growing multi-cloud and multi-AI-vendor footprint. You'll set technical direction for the team, influence cost strategy with infra and platform leaders across the org, and turn ambiguous "why did spend spike" questions into durable systems and self-service tooling. We're a small, high-leverage team - you'll have outsized influence on how Affirm thinks about cost.

Responsibilities

• Set technical strategy for your team on a year-long time scale, and help your team tie it together with critical, business-impacting projects.
• Collaborate across teams in the product development lifecycle by collaborating with product management, design & analytics to ensure technical sustainability, risks and trade-offs are well understood and managed.
• Act as a force-multiplier for your team through your definition and advocacy of technical solutions and operational processes.
• Take ownership of your team’s operations and availability by ensuring you have the right monitoring, triage rotations, playbooks, policies, testing, and alerting in place to support “keep the lights on” & on-call efforts.
• Foster a culture of quality and ownership on your team by setting code review and design standards for your team, and advocating for them beyond your team through your writing and tech talks.
• Help develop talent on your team by providing feedback and guidance, and leading by example.

Requirements

• 8+ 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.
• Experience with a FinOps or cost-visibility platform (e.g., FinOut, CloudHealth, Kubecost, or an internal equivalent) - building dashboards, anomaly detection, or savings/waste reporting rather than just consuming them.
• Track record of building automation or tooling (Python, Terraform, or similar) that turns a manual cost-review process into a scalable, self-service system - not just one-off analysis.
• Hands-on experience with cloud billing/cost data at scale (AWS Cost & Usage Reports, Snowflake or similar warehouses) - comfortable writing complex SQL to model spend, allocate cost, and build unit-economics views from raw billing data.
• Experience delivering major features, system components, or deprecating existing functionality in a system through the definition of a technical and execution plan. You write high-quality code that is easily understood and used by others.
• Thrive in ambiguity, and are comfortable moving from low-level language idioms all the way to the architecture of large systems to understand how they work.
• Demonstrated growth and impact trajectory that shows you have mastered gathering and iterating on feedback from your engineering and cross-functional peers.
• Strong verbal and written communication skills that support effective collaboration with our global engineering team.

We Offer

• Competitive Salary: CAD $181,000 - $241,000 per year.
• Health Coverage: 100% subsidized medical coverage, dental, and vision for you and your dependents.
• Spending Stipends: Monthly stipends for health, wellness, and tech spending.
• Flexible Time Off: Generous holiday calendars and flexible time off to recharge.
• Equity Rewards: Eligibility for equity rewards offered by Affirm Holdings, Inc. (parent company).
• Employee Stock Purchase Plan (ESPP): Opportunity to buy Affirm stock at a discount.

About the Company

Affirm is proud to be a remote-first company. Most roles can be done from almost anywhere within the country of employment. Some positions may occasionally require in-person work at an Affirm office, and a few are office-based due to the nature of the work. All new hires will be invited to attend an in-person onboarding experience.

Our benefits reflect our commitment to care, transparency, and flexibility. We’re committed to providing an inclusive interview process, including accommodations for candidates with disabilities. If you need support, we’re happy to help.

For positions based in San Francisco or Los Angeles: Affirm considers qualified applicants with arrest and conviction records, as required by law.

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