SECTION I · THE BRIEF
Brief #98089Updated 21 AUG 2026SAN FRANCISCO, CAYcY COMBINATOR
Employbl Company Profile

Founding Engineer — ML Platforms Engineer

Cumulus Labs is an inference platform for production AI. IonRouter, our public API, runs every class of workload from language to vision to multimodal at best-in-class speed and price, powered by Ion, our proprietary…

Location
San Francisco, CA
Company size
2–10
Posted
1mo ago
Via
Yc
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  • 01Comp band & equity packageLocked
  • 02Seniority & experience requirementsLocked
  • 03Interview process & rubricLocked
  • 04Hiring manager & team contextLocked
  • 05Growth trajectory in this roleLocked
  • 06Offer & decision timelineLocked

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Founding Engineer — ML Platforms Engineer

Cumulus Labs· San Francisco, CA, USView company profile


Job title
Founding Engineer — ML Platforms Engineer
Job location
San Francisco, CA, US
Job description
## About the role Cumulus Labs builds the software that turns raw GPU capacity into fast, cheap, production AI. We're looking for an ML Platforms Engineer to help build and run the orchestration layer underneath our inference and agent products, the system that schedules workloads, allocates GPUs, and keeps a heterogeneous, multi-cloud fleet running at high utilization. We care more about how you think than which languages are on your resume. Our stack today includes Go, Kubernetes, and Terraform, but we're looking for someone who can walk into any part of a production system, understand it, and make it better, not someone who only knows one toolchain. ## What you'll do - Build and extend our GPU orchestrator: scheduling, fractional allocation, live workload migration across GPUs with no downtime - Design and evolve multi-tenant primitives: quotas, isolation, usage metering, a tenant-facing inference gateway - Own observability for the fleet: metrics, logs, and traces at scale - Debug hard, systems-level problems across the stack, from scheduling logic down to GPU memory and networking - Make real architectural decisions, not just implement someone else's design - Ship fast, own your systems end to end, and work directly with the founder ## What we're looking for - Excellent fundamentals: data structures, algorithms, distributed systems concepts, and the judgment to apply the right pattern to the right problem - Real production experience, ideally with systems that had to stay up and scale under load - Strong design instincts: you can reason about tradeoffs, not just follow a framework's conventions - Fast learner who can go deep in unfamiliar territory; specific experience with Go or Kubernetes is a plus, not a requirement - Comfortable using modern AI coding tools (we use Claude Code heavily) to move fast without losing rigor - You want to work in person, in a small team, solving problems nobody has solved before ## Why Cumulus We're small, early, and building the systems layer for the next generation of AI infrastructure. You'll own real infrastructure from day one, not tickets in a backlog.
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Where this role is based

San Francisco, CA

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Cumulus Labs headquarters

San Francisco, CA

Company size

2–10 employees

Founded

2025

Total raised

$500,000

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Funding rounds