Member of Technical Staff, Pre-Training Data Quality Engineer

The role

You will own upstream data quality for LLM pre-training as a specialist or generalist. You will design automated QA methods, build reusable pipelines, and partner with research teams to translate requirements into measurable quality signals.

What you will do

• Own upstream data quality for LLM pre-training
• Partner with research and pre-training teams to translate requirements into measurable quality signals
• Provide actionable feedback to external data vendors
• Design, validate, and scale automated QA methods
• Build reusable QA pipelines for pre-training teams
• Monitor and report on data quality over time
• Drive continuous iteration on quality standards, processes, and acceptance criteria

Required qualifications

• Strong engineering fundamentals with experience building data pipelines, QA systems, or evaluation workflows for pre-training data
• Detail-oriented with an analytical mindset
• Solid understanding of how data quality impacts pre-training
• Experience designing and validating automated quality checks
• Proficiency in Python and building ML / LLM workflows
• Comfortable debugging and writing scalable code
• Experience working with large datasets and automated evaluation or quality-checking systems
• Familiarity with how LLMs work and can describe how models are trained and evaluated
• Excellent communication skills

Benefits

• Salary and equity
• Stock options
• Comprehensive medical, dental, vision, and life
• Annual wellness allowance
• Lunch and dinner provided in the office daily
• 22 weeks paid parental leave for all new birthing and non-birthing parents, including adoptive and surrogate journeys
• Unlimited paid time off in the U.S.
• 30 days paid time off in the U.K.
• Visa sponsorship support
• Regular off-sites, happy hours, and team celebrations

Before you apply

• This position may require access to technology or source code subject to the U.S. Export Administration Regulations
• Any offer of employment for this role may be conditioned on the Company's ability to provide the candidate with access to such technology or source code in compliance with applicable U.S. export contr

About the company

Reflection is a research lab making intelligence open and accessible for everyone to use, customize, and build on. They build open models to help shape the future of AI.