Backend/API Platform Engineer — Multi-Tenant, High-Performance

RadixArk; Palo Alto (CA); On-site; USD 200,000 - 400,000; Full time

Job summary

RadixArk is seeking a Member of Technical Staff — Backend/API Platform Engineer to design and build the API layer, control plane, and platform services powering SGLang and Miles. You will implement REST/gRPC APIs, authentication, multi-tenancy, and monitoring to support thousands of developers and companies.

You will bridge high-performance inference systems with production-grade platform engineering, collaborating with systems engineers and cloud infrastructure teams to ensure scalable, secure,

Qualifications

• 4+ years experience building production backend systems, APIs, or platform infrastructure.
• Bachelor's or Master's in Computer Science, Engineering, or equivalent industry experience
• Strong proficiency in Python, Go, or Rust with production-quality code standards
• Experience designing and building REST/gRPC APIs at scale
• Solid understanding of distributed systems, databases, caching, and message queues
• Experience with authentication, authorization, rate limiting, and multi-tenancy
• Familiarity with cloud platforms (AWS, GCP, Azure) and Kubernetes
• Experience with monitoring and observability tools (Prometheus, Grafana, DataDog)
• Understanding of ML serving infrastructure or high-throughput systems is a plus

Responsibilities

• Design and build production APIs for SGLang and Miles: REST/gRPC endpoints, client SDKs, API versioning
• Implement authentication, authorization, and rate limiting systems for multi-tenant deployments
• Build control plane infrastructure: job scheduling, resource allocation, model deployment management
• Create monitoring, logging, and observability systems for production inference and training workloads
• Design and implement billing integration, usage tracking, and quota management
• Build management dashboards and admin tools for cluster operations
• Ensure API reliability, performance, and security at scale
• Implement multi-tenancy isolation and security boundaries
• Create deployment automation, CI/CD pipelines, and rollback procedures
• Write comprehensive API documentation and integration guides
• Partner with Systems Engineers to optimize end-to-end latency from API → serving layer
• Debug production issues and implement reliability improvements

Skills

Python

Go

Rust

APIs

Distributed systems

Education

Bachelor's or Master's in CS/Engineering

Tools

AWS

GCP

Azure

Kubernetes

Prometheus

Grafana

DataDog

Job description

RadixArk is seeking a Member of Technical Staff — Backend/API Platform Engineer to design and build the API layer, control plane, and platform services powering SGLang and Miles. You will implement REST/gRPC APIs, authentication, multi-tenancy, and monitoring to support thousands of developers and companies.

You will bridge high-performance inference systems with production-grade platform engineering, collaborating with systems engineers and cloud infrastructure teams to ensure scalable, secure,