Staff Software Engineer, Backend (Capacity Modeling)

About Affirm and the Team

Affirm operates to provide consumers a transparent, predictable payment solution with no hidden fees or compromises on what matters. The Capacity Modeling team plays a key role in ensuring Affirm's infrastructure can handle anticipated demand, particularly during peak sales periods. They develop and maintain statistical models that convert forecasts like checkout volume and app activity into resource requirements including CPU, memory, and connection counts. These models then guide capacity recommendations such as pod scaling, infrastructure sizing, and autoscaling adjustments across different regions and environments. The scope includes compute resources as well as services like ElasticCache, DynamoDB, and AuroraDB.

Key Responsibilities

• Define and drive the technical vision and strategy for the team on an annual horizon, aligning with high-impact business initiatives.
• Collaborate extensively across product management, design, and analytics to manage technical sustainability, risks, and trade-offs effectively during the product lifecycle.
• Serve as a multiplier for the team by advocating sound technical solutions and operational processes.
• Take full responsibility for operational excellence, including monitoring, incident response, on-call rotations, and establishing robust playbooks and alerting practices to maintain system availability.
• Promote a culture of ownership and quality by setting and enforcing standards for code reviews and system design, and sharing best practices through internal knowledge sharing like documentation and tech talks.
• Mentor and develop team members through constructive feedback, guidance, and leading by example.

Candidate Profile

• Minimum of 8 years designing, developing, and deploying backend systems at scale, proficient in languages such as Python or Kotlin.
• Demonstrated experience building highly available distributed systems leveraging AWS, MySQL, Spark, and Kubernetes.
• Background supporting scaling strategies for large-scale sales events including Prime Day, Black Friday, Cyber Monday, or other major holidays.
• Expertise tuning autoscaling parameters, optimizing CPU and memory utilization, and implementing multi-threading in compute-intensive workloads.
• Proven track record of delivering major product features, system components, or systematically deprecating features by defining strong technical and execution strategies; writes clear, maintainable, high-quality code.
• Comfortable navigating ambiguity and analyzing system architecture from low-level code to the broader distributed system design.
• A history of incorporating feedback and continuously improving technical impact and collaboration skills.
• Effective verbal and written communication skills to work collaboratively with a global engineering team.

Compensation and Benefits

This role corresponds to Pay Grade P and Equity Grade 7. Entry-level hires typically start near the bottom of the salary band. Total compensation may include monthly stipends for technology and wellness support, and comprehensive benefits with 100% subsidized medical, dental, and vision coverage for employees and dependents. Eligible employees may also participate in equity programs offered by Affirm Holdings, Inc.

Base salary range in Canada: CAD 181,000 to 241,000 annually.

Work Arrangement

This is a remote-first position with flexibility, supporting work from nearly anywhere within the country of employment. Some roles may require occasional in-person attendance, particularly onboarding and select activities.

Additional Information

• Affirm is committed to inclusive hiring and provides accommodations for candidates with disabilities.
• Applicants located in San Francisco or Los Angeles: Affirm complies with applicable laws relating to consideration of arrest and conviction records.