ABOUT THE ROLE:

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.

BASIC QUALIFICATIONS:

• Strong software engineering fundamentals.
• Ability to write clean, maintainable code and learn new codebases quickly.
• Strong problem-solving skills and comfort working through ambiguity.
• Experience building software through internships, projects, research, open-source work, startups, or full-time roles.
• 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.

PREFERRED SKILLS AND EXPERIENCE:

• 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.

You do not need to know every technology listed below. We care more about strong fundamentals, learning speed, and ability to ship.

• React
• Golang
• Python
• Rust
• gRPC
• Java / Scala

COMPENSATION AND BENEFITS:

$150,000 - $350,000 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.