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Member of Technical Staff - Data Ingestion Engineer

Reflection· Research
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San Francisco, CA, London, New York, NYFull-timePosted 9mo ago

About the role

Data ingestion engineer role focused on building and operating large-scale ingestion systems to turn open web and other sources into reliable, well-structured corpora for pre-training frontier models. Own ingestion, extraction, normalization, versioning, and delivery to pre-training pipelines, collaborating with researchers to optimize data impact on model performance.

Responsibilities

  • Build and operate large-scale data ingestion systems for pre-training, including web crawling, extraction, and dataset delivery
  • Run experiments to evaluate crawling strategies, extraction methods, and ingestion tradeoffs
  • Analyze ingested data to identify gaps, redundancy, and areas to improve
  • Build ingestion pipelines that scale reliably across large data campaigns
  • Develop specialized crawlers for high-priority data sources
  • Review code, debug production issues, and continuously improve ingestion infrastructure

Qualifications

  • Experience building web crawling, data ingestion, or large-scale data acquisition systems using Ray, Beam, Spark, or similar technologies
  • Familiarity with how LLMs are trained and evaluated, and an intuition for what makes data useful for training
  • Comfortable working with very large datasets (multi-TB to PB scale) and building systems that are observable, testable, and maintainable
  • Comfortable designing experiments and using data to guide system improvements
  • Excellent communication skills. You can explain system behavior. You consider and communicate tradeoffs clearly

Skills

Required:Large-scale data ingestion systemsWeb crawling / data extractionExperiment design and data-driven iterationObservability and reliabilityCommunication

Benefits

  • Top-tier compensation: Salary and equity structured to recognize and retain our talent globally
  • Stock options: Everyone who joins and contributes to Reflection's success gets to share in the upside through stock options
  • Health & wellness: Comprehensive medical, dental, vision, and life, with an annual wellness allowance
  • Meals: Lunch and dinner are provided in the office daily
  • Life & family: 22 weeks paid parental leave for all new birthing and non-birthing parents, including adoptive and surrogate journeys
  • Vacation days: Unlimited paid time off in the U.S. and 30 days in the U.K
  • Sponsorship support: We sponsor visas to help exceptional talent join our team and support long-term immigration pathways where applicable
  • Team building: Regular off-sites, happy hours, and team celebrations
Last updated Oct 1, 2026. Interested? Apply on the company site.

About Reflection

Building frontier open intelligence

Building frontier open intelligence.

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