SECTION I · THE BRIEF
Brief #75175Updated 29 OCT 2026 PALO ALTO, CAGreenhouse
Employbl Company Profile

Software Engineer, RL Training Framework

AI company building the Grok family of models and consumer and API products on top of them.

Location
Palo Alto, CA
Company size
1,000–2,000
Posted
Yesterday
Via
Greenhouse
Section II · Full ProfileFree with an account
  • 01Comp band & equity packageLocked
  • 02Seniority & experience requirementsLocked
  • 03Interview process & rubricLocked
  • 04Headcount & which departments are hiringLocked
  • 05Growth trajectory in this roleLocked
  • 06Offer & decision timelineLocked

Free · 2 minutes · the funding and stack behind this role

Software Engineer, RL Training Framework

xAI· Palo Alto, CAView company profile


Job title
Software Engineer, RL Training Framework
Job location
Palo Alto, CA
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, RL TRAINING FRAMEWORK

The RL infrastructure team is looking for an engineer to help develop our RL training framework.

RESPONSIBILITIES:

  • Design and implement the systems backing all RL workloads at SpaceXSI, from small scale ablations to production training runs
  • Profile, debug, and optimize end-to-end training performance
  • Improve scalability and observability of the RL stack

BASIC QUALIFICATIONS:

  • Experience with Python, Jax, Rust, and/or C++

PREFERRED SKILLS AND EXPERIENCE:

  • Experience building, debugging, and optimizing efficiency of large-scale distributed systems
  • Experience with large scale LLM training infrastructure
  • Strong knowledge of reinforcement learning techniques
  • Experience with RL numerics
  • Comfortable diving into unfamiliar areas and solving problems at all levels of the stack

COMPENSATION AND BENEFITS:

$180,000 - $440,000 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.

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xAI headquarters

Palo Alto, CA

Company size

1,000–2,000 employees

Founded

2023

Total raised

$42,882,486,272

View company profile ↗

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Funding rounds