Senior Backend Engineer - AI Platform (Remote)

Affirm, Inc.; St. Louis (MO); Remote; USD 173,000 - 233,000; Full time

Benefits offered by this job

Health coverage

Stipends for tech setup

Flexible time off

ESPP

Job summary

Affirm, Inc. is seeking an experienced Backend Engineer for the AI Platform team. You will design, build, and operate gateway, runtime, and evaluation services handling AI workloads at scale, with a focus on secure, scalable infrastructure and cross-team collaboration.

You will work on identity, quota, routing, and tooling integration, using Python or Kotlin, AWS, and Kubernetes, while mentoring teammates and advancing best practices in a fast-growing, remote-friendly environment.

Qualifications

• 4+ years of experience designing, developing and launching backend systems at scale.
• Experience with AWS, MySQL and Kubernetes.
• Practical experience with LLMs, agents, or AI frameworks in production.
• Ability to define a technical plan for delivering significant features.
• Strong ownership and proactive feedback seeking from your team.
• Excellent written and verbal communication for global collaboration.
• Bachelor’s degree or equivalent practical experience.

Responsibilities

• Plan, execute, and own technical decisions from design through on-call.
• Design and build gateway, runtime, and evaluation services for AI workloads.
• Implement identity, quota, routing, caching, and failover controls.
• Partner with security, infra, and product teams to set guardrails.
• Create and monitor metrics and maintain operational health.
• Set code review standards and contribute to tech talks.
• Mentor engineers and drive best practices across the team.
• Use AI tools daily to improve development and ops.

Skills

Backend design

Python/Kotlin

Distributed systems

AWS

MySQL

Kubernetes

Education

Bachelor's degree or equivalent

Tools

LLM gateways

MCP

Eval systems

Job description

Affirm, Inc. is seeking an experienced Backend Engineer for the AI Platform team. You will design, build, and operate gateway, runtime, and evaluation services handling AI workloads at scale, with a focus on secure, scalable infrastructure and cross-team collaboration.

You will work on identity, quota, routing, and tooling integration, using Python or Kotlin, AWS, and Kubernetes, while mentoring teammates and advancing best practices in a fast-growing, remote-friendly environment.