Software Engineer - Evals
Confirmed on the employer's own hiring board on Oct 16, 2026. First seen by Alion on Jul 22, 2026. xAI scores A on the Alion truth index.
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 understand the universe and help expand humanity’s knowledge and capabilities. We work across the full Super Intelligence stack: compute (Colossus supercomputers), models (Grok), and applications (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.
You will own and elevate our mission-critical research platform that directly accelerates SpaceXSI's frontier work.
The evals team creates and executes instruments for measuring model capabilities and behaviors. These instruments are used to clean datasets, provide feedback for experiments, and track growth throughout training. The evals team also diagnoses why agents fail and how to make improvements both short and long term. We manage the execution infrastructure, design data sets and grading schemes.
You will design, build, and ship delightful and bulletproof systems that engineers love to use every day. This role values a strong attention to details, first principles reasoning, and great taste.
We are open to all levels from new grads to senior engineers.
Requirements
- Software engineering proficiency and 3+ years of experience actively writing code.
- A track record of shipping high quality projects and a strong sense of urgency.
- Exceptional product taste - you have a sharp sense for what “good” looks like in outputs, and you can translate fuzzy notions of quality, helpfulness, truthfulness, and safety into concrete, measurable criteria.
- Strong attention to detail.
Bonus Points
- Previously founded a startup or joined a fast-growing early-stage startup.
- Familiarity with AI/ML workflows, annotation tools, or evals.
- Experience creating and maintaining component libraries, design systems, or internal tools.
COMPENSATION AND BENEFITS:
$175,000 - $275,000 USD
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.
SpaceXSI is an equal opportunity employer. For details on data processing, view our Recruitment Privacy Notice.