Staff Software Engineer, Backend (Capacity Modeling)

About the role

The Capacity Modeling team at Affirm ensures the company can safely handle forecasted traffic, especially during peak sales events, by translating demand forecasts into concrete, testable capacity plans. This involves building and maintaining statistical capacity models that map traffic inputs to resource outputs and converting forecasts into recommended capacity settings.

Responsibilities

• Set technical strategy for the team on a year-long time scale
• Collaborate with product management, design & analytics to ensure technical sustainability, risks, and trade-offs are well understood and managed
• Act as a force-multiplier for the team through the definition and advocacy of technical solutions and operational processes
• Take ownership of the team’s operations and availability by ensuring the right monitoring, triage rotations, playbooks, policies, testing, and alerting are in place to support “keep the lights on” and on-call efforts
• Foster a culture of quality and ownership on the team by setting code review and design standards and advocating for them beyond the team through writing and tech talks
• Help develop talent on the 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
• An extensive track record of developing highly available distributed systems using technologies like AWS, MySQL, Spark, and Kubernetes
• Experience supporting scale up and down of large-scale sales events such as Prime Day, Black Friday, Cyber Monday, or other sales holidays
• Tuned autoscaling, CPU/Memory, and multi-threading for compute-type workloads
• Delivered major features, system components, or deprecated existing functionality in a system through the definition of a technical and execution plan
• Write high-quality code that is easily understood and used by others
• Comfortable moving from low-level language idioms to the architecture of large systems to understand how they work
• Growth and impact trajectory demonstrates mastery of gathering and iterating on feedback from engineering and cross-functional peers
• Strong verbal and written communication skills to support effective collaboration with the global engineering team

Qualifications

• Equivalent practical experience or a Bachelor’s degree in a related field

Skills

• Experience with AWS, MySQL, Spark, and Kubernetes
• Experience with Python or Kotlin
• Experience with high availability and distributed systems
• Experience with scaling and managing large-scale sales events
• Experience with auto-scaling, CPU/Memory, and multi-threading
• Experience with feature delivery and system component deprecation
• Ability to write high-quality, understandable code
• Ability to understand and communicate complex technical concepts

Benefits

• Base Pay Grade - P
• Equity Grade - 13
• Remote-first company
• Competitive benefits package including health care coverage, flexible spending wallets, time off, ESPP, and more