Sr. Software Engineer, Pretraining Data
Cursor · Palo Alto, CA
About this role
**SpaceXSI — Sr. Software Engineer, Pretraining Data** SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams build the full Super Intelligence stack—from Colossus supercomputers and Grok models to a suite of applications (including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X). We’re looking for Senior Software Engineers to build and own the data systems behind our frontier models’ initial training. --- ## Responsibilities - **Data Platform:** Design, build, and scale distributed infrastructure that transforms raw web, code, multimodal, and acquired data into training-ready datasets. Own high-throughput pipelines, orchestration, and tooling for fast, reliable, observable, and reproducible processing at massive scale, with end-to-end visibility into lineage, freshness, and pipeline health. - **Data Quality:** Build and deploy high-performance models/algorithms to classify, rank, deduplicate, filter, and clean training data at extreme throughput. Run rigorous experiments across data mixtures, sampling strategies, and quality thresholds to quantify impact on training loss and downstream evaluations—then translate findings into production systems. - **Crawling:** Build and optimize large-scale web crawling infrastructure across URL discovery, prioritization, host scheduling, fetching, parsing, and content extraction. Improve coverage, efficiency, and reliability using intelligent scheduling, anti-bot resilience, robust extraction, and automated recovery. - **Technical Leadership & Collaboration:** Lead complex initiatives across Data Platform, Data Quality, Crawling, Acquisition, and model training teams. Influence technical direction, drive architectural decisions, mentor engineers, and translate improvements into measurable model performance gains. --- ## Basic Qualifications - **5+ years** of professional software engineering experience building distributed systems and/or large-scale data infrastructure. --- ## Preferred Skills & Experience - Strong infrastructure or data platform background (including outlier depth) - High-slope engineer who has moved unusually fast (e.g., staff-level ownership within a few years) or brings relevant domain experience - Able to architect and ship end-to-end with high ownership; debug complex systems independently; work alongside AI agents - Strong intuitions about large-scale distributed systems and running them reliably at frontier scale - Track record of leading technical projects across teams and mentoring other engineers - Excited to learn how pretraining data shapes model quality and to build systems with ownership and visibility into frontier training runs --- ## Additional Requirements - **Onsite role:** Must be able to work in person at the **Palo Alto** office. --- ## Compensation & Benefits - **Annual salary range:** **$220,000 – $357,000 USD** (case-by-case based on knowledge/skills, education, and experience) - Total rewards include **equity**, comprehensive **medical/vision/dental**, **401(k)**, short & long-term disability, life insurance, and various discounts/perks.
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