Software Engineer, Security

Cursor; San Francisco (CA); On-site; USD 140,000 - 225,000; Full time

Benefits offered by this job

Health insurance

Job summary

SpaceXSI, based in the San Francisco Bay Area, is seeking a Software Engineer, Security to defend our AI stack. You will build systems to test hypotheses, run ablations, and learn from rollouts to improve model safety.

You will implement least-privilege cloud access, secure environments for agents, and data handling frameworks. Onsite interviews will follow initial technicals at our SF office.

Qualifications

• Experience building or scaling secure systems in fast-moving environments.
• Think like a builder and an attacker to anticipate vulnerabilities.
• Care about developer experience while keeping solutions secure.
• Willingness to move quickly and own problems end-to-end.

Responsibilities

• Build AI augmented code review to improve critical systems at the right time.
• Build a least-privilege and JIT system for cloud access enforcing least privileges.
• Implement a safe environment for agents to engage with code.
• Implement a framework for securely handling agent manipulation of user systems (e.g., MCP tool calls and command execution).
• Implement a paved road for preventing inappropriate data from being logged.]

Skills

Security-focused engineer

Threat modeling

Secure defaults

Developer experience

Job description

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, SECURITY

You form hypotheses about why data is helping or misleading the model, build the systems to test them, run ablations, and read the rollouts to find the bug, shortcut or mismatch behind a result. Every flaw you catch, or miss, shows up in what the next Grok models learn.

RESPONSIBILITIES

• Build AI augmented code review to get involved in important systems at the right time
• Build a least-privilege and JIT system for cloud access that enables engineers and enforces least privileges
• Implement a safe environment for agents to engage with code
• Implement a framework for securely handling agent manipulation of user systems (e.g., MCP tool calls and command execution)
• Implement a paved road for preventing inappropriate data from being logged

BASIC QUALIFICATIONS

• Experience building or scaling secure systems in fast-moving environments

PREFERRED SKILLS AND EXPERIENCE

• A strong software engineer first, with security as your superpower
• Think like both a builder and an attacker: you anticipate vulnerabilities before they become issues
• Care about developer experience, building solutions that are secure and frictionless
• Comfortable moving quickly, owning problems end to end, and iterating with limited guidance
• Strong opinions on secure defaults, but can balance pragmatism with rigor
• Enjoy working on small, high-talent teams where impact is magnified
• Motivated by protecting developers and users, and you see security as an enabler

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.