Software Engineer, Pretraining

San Francisco

Our mission is to automate coding. The first step in our journey is to build the best tool for professional programmers, using a combination of inventive research, design, and engineering. Our organization is very flat, and our team is small and talent dense. We particularly like people who are truth-seeking, passionate, and creative. We enjoy spirited debate, crazy ideas, and shipping code.

About the Position

We’re looking for Software Engineers to build the data systems behind our frontier coding models’ initial training. You’ll work on large-scale crawling, data platform, and pipeline infrastructure, turning raw dumps into the datasets our models train on, and making iteration with researchers fast and reliable.

Responsibilities

Data Quality Team

• Build and own high-throughput, fully telemetered data pipelines that process frontier-scale data with end-to-end traceability.
• Train and ship models that classify, rank, filter, clean, and identify data at extreme throughput.
• Design and run scaling-ladder experiments on data-mixture, repeatability, and quality depth.
• Partner tightly with Data Acquisition to hunt down missing or low-quality sources, and with the training teams to close the loop on what actually moves loss and downstream evals.
• Treat data quality as a systems problem and a research problem.

Data Platform Team

• Build the platform that turns raw web, code, multimodal, and acquired data into training-ready datasets for frontier pretraining runs.
• Own the pipelines, orchestration, and tooling that make pretraining data iteration fast, reliable, observable, and reproducible at scale.
• Create clear signals for data quality, lineage, freshness, and pipeline health.
• Partner with initial training, crawling, data quality, and acquisition teams to turn new data ideas into measurable improvements in loss, evals, and model capability.

Crawling Team

• Build and scale the web crawling systems that discover, schedule, fetch, and parse high-quality documents across the open web for initial training.
• Improve URL seeding, scoring, and fair host scheduling.
• Raise crawl success and parsing quality.
• Debug and harden complex crawl infrastructure end-to-end for availability, recovery, and ingestion lag.
• Automate delivery of crawl datasets into the data pipeline.

Requirements

• Strong infrastructure or data platform background, and ideally a spike of outlier depth somewhere (crawling/search infra is a plus, not a hard requirement).
• High-slope engineer who has moved unusually fast - for example, staff-level ownership within a few years - or you bring deep domain experience.
• Ability to architect and ship end-to-end with high ownership, debug complex systems independently, and work alongside AI agents.
• Strong intuitions about large-scale distributed systems.
• Excitement to learn how pre-training data shapes model quality, and desire for ownership and visibility in building systems that feed frontier training runs.

We Offer

• Opportunity to work in a flat, talent-dense organization.
• Collaborative environment that values spirited debate, crazy ideas, and shipping code.
• Competitive compensation package.

About the Company

Our mission is to automate coding. We are building the best tool for professional programmers, using a combination of inventive research, design, and engineering.