Software Engineer, Model Routing & Inference

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars.

SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next.

About the Role

As a Software Engineer on the Model Routing & Inference team at SpaceXAI, you'll build the inference platform that powers every AI interaction in the product.

This team owns the full inference path: making Cursor's AI faster, more reliable, and more cost-effective at a scale few teams in the world get to operate at. Every agent session, every tab completion, and every chat message flows through your stack.

Example projects include...

• Building and evolving our inference gateway, a single abstraction over every provider's API semantics, so model onboarding becomes a config change.

• Designing intelligent cross-provider failover so no single provider outage causes user-visible degradation.

• Designing routing backpressure and admission control so traffic spikes don't cascade into providers.

You may be a fit if

• You have deep experience building high-throughput, low-latency distributed systems, especially in inference serving, traffic routing, or real-time data pipelines.

• You're comfortable reasoning about cost/performance tradeoffs at scale (GPU utilization, provider economics, capacity planning).

• You have strong software engineering fundamentals and enjoy shipping production systems that handle millions of requests.

• You make good calls in the gray area: weighing reliability, cost, latency, and user experience when there isn't a single "right" answer.

Applying

If there appears to be a fit, we'll reach to schedule 2-3 short technicals. After, we'll schedule an onsite in our office, where you'll work on a small project, discuss ideas, and meet the team.

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