Senior Backend Engineer, AI Platform (Remote-First)

Affirm, Inc.; Phoenix (AZ); Remote; USD 173,000 - 255,000; Full time

Benefits offered by this job

Remote-first with flexibility

Equity

Health & wellness stipends

Job summary

Affim is hiring for an AI Platform leader who will own end-to-end backend decisions, design scalable gateways and runtimes, and govern AI workloads used by millions of users. You’ll partner across security, infra, and product teams to implement guardrails, metrics, and high-availability architectures.

You will mentor engineers, drive best practices in design and testing, and advocate for simple, extensible systems while shaping the company’s approach to AI tools and models.

Qualifications

• 4+ years of experience designing, developing and launching backend systems at scale.
• Experience building highly available distributed systems (AWS, MySQL, Kubernetes).
• Practical experience building with LLMs, agents, or AI frameworks in production.
• Understanding AI usage and infrastructure to support AI workloads.
• Defined technical plans for delivering significant features with simple, extensible design.
• Strong ownership, feedback-seeking, and proactive growth mindset.
• Excellent written and verbal communication for collaboration with global teams.
• Bachelor’s degree or equivalent practical experience in a related field.

Responsibilities

• Plan, execute, and own technical decisions and projects within the AI Platform team.
• Design and build gateway, runtime, and evaluation services for AI workloads at scale.
• Implement identity, quota, routing, caching, and failover controls across models and tools.
• Collaborate with security, infra, and product teams to set guardrails for agent workloads.
• Create and monitor metrics; own the operational health, monitoring, and runbooks.
• Set and improve code review standards and champion them via talks and writing.
• Leverage AI tools daily to multiply team output in design, review, and operations.
• Educate and mentor engineers; promote best practices in design, coding, and testing.

Skills

Python

Kotlin

Backend design

Distributed systems

Education

Bachelor’s degree or equivalent

Tools

AWS

MySQL

Kubernetes

Job description

Affim is hiring for an AI Platform leader who will own end-to-end backend decisions, design scalable gateways and runtimes, and govern AI workloads used by millions of users. You’ll partner across security, infra, and product teams to implement guardrails, metrics, and high-availability architectures.

You will mentor engineers, drive best practices in design and testing, and advocate for simple, extensible systems while shaping the company’s approach to AI tools and models.