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.
X Ads is one of the highest-leverage product areas at X. You’ll work on systems that operate at massive scale, directly affect the business, and are being rebuilt with modern infrastructure and AI at the center. This is an opportunity to join a small, fast-moving team where early-career engineers can take on real ownership, learn from strong engineers, and ship products that matter.
We’re looking for high-slope software engineers who want to help rebuild and transform the X Ads Platform using SpaceXSI's infrastructure and AI stack. This role is a great fit for engineers who are early in their careers but learn quickly, ship fast, and want to work on products and systems that operate at massive scale. You do not need to have deep ads experience already, but you should be excited to learn how large-scale advertising systems work and how AI can make ads more relevant, useful, and effective.
You’ll work across product, backend systems, infrastructure, and AI-powered features that directly impact the majority of X’s revenue.
RESPONSIBILITIES:- Build and ship product features across the X Ads Platform
- Work on systems related to ad delivery, targeting, optimization, measurement, and advertiser experience
- Use SpaceXSI's infrastructure and AI capabilities to improve the performance and quality of advertising products
- Contribute to distributed systems that need to be reliable, fast, and scalable
- Collaborate closely with engineers, product leads, and cross-functional partners to turn ideas into working products
- Learn quickly, take ownership, and operate in a fast-moving environment where high-quality execution matters
- Debug, maintain, and improve production systems that serve real users and drive significant business impact
- 5+ years of experience building software through internships, projects, research, open-source work, startups, or full-time roles
- Strong software engineering fundamentals
- Ability to write clean, maintainable code and learn new codebases quickly
- Strong problem-solving skills and comfort working through ambiguity
- Interest in backend systems, distributed systems, data pipelines, product engineering, or AI applications
- A bias toward action: you like shipping, learning from real users, and improving quickly
- Strong ownership mindset and willingness to take responsibility for meaningful parts of the product
- Excitement about building high-quality product experiences for advertisers and users
- Experience with ads, recommendations, search, ranking, marketplaces, payments, analytics, or growth systems
- Experience working with large-scale backend systems or data processing pipelines
- Experience with React, Golang, Python, Rust, gRPC, Java, or Scala
- Experience with machine learning, LLMs, experimentation, ranking, or optimization systems
- Prior startup, research, internship, or high-impact project experience
- Experience with React, Golang, Python. Rust, gRPC, and/or Java/Scala
- Strong fundamentals, learning speed, and ability to ship
$180,000 - $330,000 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.
xAI Palo Alto, California, USA Office
1450 Page Mill Road, Palo Alto, CA, United States
xAI San Francisco, California, USA Office
3180 18th St., San Francisco, CA, United States
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