[Hiring] Senior Software Engineer, Backend (AI Platform) @Affirm

Role Description

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.

Affirm's engineering team is building a large-scale, fault-tolerant, and global infrastructure that is shared across multiple financial products, merchants, and vendors. Ensuring that our infrastructure is transparently available to all engineers is critical to the success of the business.

The AI Platform team owns Affirm's paved path for building, running, evaluating, and governing AI systems. Our customers are not only Affirm users, but also every engineer and a growing set of production workloads at Affirm. As a team, we are responsible for:

• Building and exposing simple, governed interfaces to models, tools, and agents.
• Ensuring identity, cost attribution, reliability, and security are built in.
• Managing components like the LLM Gateway, MCP Gateway, Agent Runtime, and the evals and observability layer.

We are early: the gateway is in daily use across engineering, the first production agent is live, and the next year takes us from developer productivity to production inference and agents.

Qualifications

• 4+ years of experience designing, developing, and launching backend systems at scale using languages like Python or Kotlin.
• Track record of developing highly available distributed systems using technologies like AWS, MySQL, and Kubernetes.
• Practical experience building with LLMs, agents, or AI frameworks in production.
• Understanding of AI usage and the infrastructure needed to support and leverage AI workloads.
• Experience defining a technical plan for the delivery of a significant feature or system component.
• Proficient at making significant changes in a large code base.
• Strong verbal and written communication skills.
• This position requires either equivalent practical experience or a Bachelor’s degree in a related field.

Requirements

• Ownership of growth, proactively seeking feedback from team, manager, and stakeholders.
• Ability to educate, mentor, and grow engineers in the team.
• Drive best practices around design, coding, and testing.

Benefits

• Health coverage at no cost: 100% of premiums for employees and their dependents.
• Monthly stipends for tech setup and health and wellness options.
• Flexible time off and generous holiday calendars.
• Employee stock purchase plan (ESPP) to buy Affirm stock at a discount.

Company Description

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.