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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.\nSpaceXSI 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.\nSR. MODEL ENGINEER, RL TRAINING FRAMEWORK\nThe RL infrastructure team is looking for an engineer to help develop our RL training framework.\nRESPONSIBILITIES:\nDesign and implement the systems backing all RL workloads at SpaceXSI, from small scale ablations to production training runs\nProfile, debug, and optimize end-to-end training performance\nImprove scalability and observability of the RL stack\nBASIC QUALIFICATIONS:\nExperience writing production-quality code in Python, PyTorch, JAX, Rust, or C++\nExperience training large models (e.g., pre-training, post-training, fine-tuning, or RL training of neural networks with 1B+ parameters)\nPREFERRED SKILLS AND EXPERIENCE:\nExperience building, debugging, and optimizing efficiency of large-scale distributed systems\nExperience with large scale LLM training infrastructure\nExperience with RL numerics\nStrong knowledge of reinforcement learning techniques\nComfortable diving into unfamiliar areas and solving problems at all levels of the stack\nCOMPENSATION AND BENEFITS:\n$180,000 - $400,000 USD\nBase 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.\nSpaceXSI is an equal opportunity employer. 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