Staff Software Engineer, Backend (Capacity Modeling)

Affirm is reinventing credit to make it more honest and friendly, giving consumers the flexibility to buy now and pay later without any hidden fees or compounding interest.

The Capacity Modeling team ensures affirm can safely handle forecasted traffic—especially during peak sales events—by translating demand forecasts into concrete, testable capacity plans. They build and maintain statistical capacity models that map traffic inputs (e.g., checkout volume, app opens, batch/job activity) to resource outputs (CPU, memory, connections) and then convert those forecasts into recommended capacity settings such as pod counts, HPA ranges, and infrastructure sizing changes across regions and environments. The coverage of infrastructure resources includes not only Compute but also services such as ElasticCache, DynamoDB, AuroraDB, and more.

What You'll Do

• You will be responsible for setting technical strategy for your team on a year-long time scale, and help your team tie it together with critical, business-impacting projects.
• You will 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.
• You will act as a force-multiplier for your team through your definition and advocacy of technical solutions and operational processes.
• You 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.
• You will 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.
• You will help develop talent on your team by providing feedback and guidance, and leading by example.

What We Look For

• You have 8+ years of experience designing, developing and launching backend systems at scale using languages like Python or Kotlin.
• You have an extensive track record of developing highly available distributed systems using technologies like AWS, MySQL, Spark and Kubernetes.
• You have experience supporting scale up and down of large scale sales event such as Prime Day, Black Friday Cyber Monday, or other sales holidays.
• You have tuned autoscaling, CPU/Memory, and multi-threading for compute type workloads.
• You have 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.
• You 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.
• Your growth and impact trajectory demonstrates that you have mastered gathering and iterating on feedback from your engineering and cross-functional peers.
• You have strong verbal and written communication skills that support effective collaboration with our global engineering team.

Pay Grade - P

Equity Grade - 7

CAN base pay range per year: $178,000 - $228,000

Remote

Benefits

• Health care coverage – affirm covers all premiums for all levels of coverage for you and your dependents.
• Flexible Spending Wallets – generous stipends for spending on technology, food, various lifestyle needs, and family forming expenses.
• Time off – competitive vacation and holiday schedules allowing you to take time off to rest and recharge.
• ESPP – an employee stock purchase plan enabling you to buy shares of affirm at a discount.

We believe it’s on us to provide an inclusive interview experience for all, including people with disabilities. We are happy to provide reasonable accommodations to candidates in need of individualized support during the hiring process.

For U.S. positions that could be performed in Los Angeles or San Francisco, pursuant to the San Francisco Fair Chance Ordinance and Los Angeles Fair Chance Initiative for Hiring Ordinance, affirm will consider for employment qualified applicants with arrest and conviction records.