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.

SOFTWARE ENGINEER, MODEL ROUTING & INFERENCE

As a Software Engineer on the Model Routing & Inference team at SpaceXSI, 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.

RESPONSIBILITIES:

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

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

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

BASIC QUALIFICATIONS:

• Experience building high-throughput, low-latency distributed systems (e.g., inference serving, traffic routing, or real-time data pipelines)

• Bachelor's degree in computer science, engineering, math, or scientific discipline; OR 2+ years of professional experience building software in lieu of a degree

PREFERRED SKILLS AND EXPERIENCE:

• Comfortable reasoning about cost/performance tradeoffs at scale (GPU utilization, provider economics, capacity planning)

• Strong software engineering fundamentals and enjoying shipping production systems that handle millions of requests

ADDITIONAL REQUIREMENTS:

• If there appears to be a fit, we'll reach out 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

COMPENSATION AND BENEFITS:

The annual compensation range for this role is listed below.

Annual Salary:

$140,000 - $225,000 USD

Your actual level and base salary will be determined on a case-by-case basis and may vary based on the following considerations: job-related knowledge and skills, education, and experience.

Base salary is just one part of our total rewards package at SpaceXSI, which also includes equity, comprehensive medical, vision, and dental coverage, access to a 401(k) retirement plan, short & long-term disability insurance, life insurance, and various other discounts and perks.