New The Skills of Tomorrow: how AI-exposed is every skill in 2026? See the data →
Cursor

Software Engineer

Cursor
Apply →
senior full-time

First indexed 25 Aug 2026

Description

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.

The Data Quality team

The Data Quality team owns the entire road between raw internet-scale data and the tokens that train frontier models. This team makes sure the right data, in the right form, hits the training clusters on time and at the quality bar required to push the scaling curve.

The Data Platform Team

The Data Platform Team owns the infrastructure and pipelines that transform raw data dumps into training-ready datasets. This team improves the speed, reliability, and developer experience of our initial training data pipelines so researchers can quickly experiment with new data sources, quality filters, taxonomies, multimodal data, and data mixes that improve model performance.

The Crawling team

The Crawling team owns large-scale web crawling and parsing that feeds the top of the funnel for initial training. They discover, schedule, fetch, and parse public web content so high-quality documents become the raw scrapes that Data Quality and Data Platform turn into tokens and mixes.

Responsibilities

On the 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.

On the 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.

On the 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.
  • Work independently and alongside AI agents.

Requirements

  • You have a strong infrastructure or data platform background, and ideally a spike of outlier depth somewhere.
  • You are a high-slope engineer who has moved unusually fast.
  • You are able to architect and ship end-to-end with high ownership, debug complex systems independently, and work alongside AI agents.
  • You have strong intuitions about large-scale distributed systems.
  • You're excited to learn how pre-training data shapes model quality, and want the ownership and visibility that comes with building systems that feed frontier training runs.
This listing is enriched and indexed by YubHub. To apply, use the employer's original posting: https://cursor.com/careers/software-engineer-pretraining