Reflection · 7 months ago
Member of Technical Staff - Data Quality Engineer (Pre-training)
San Francisco, CA
Full-time
Onsite
Mid LevelReflectionAI is dedicated to building open superintelligence and making it accessible to all. The Data Quality Engineer will ensure that the data used for training models meets high standards of quality and reliability, collaborating closely with research teams to develop measurable quality signals and automate quality assurance processes.
Artificial Intelligence (AI)SoftwareFoundational AI
Responsibilities
Own upstream data quality for LLM pre-training; as a specialist or generalist across languages and modalities
Partner closely with research and pre-training teams to translate requirements into measurable quality signals, and provide actionable feedback to external data vendors
In addition to human-in-the-loop processes, you will design, validate, and scale automated QA methods to reliably measure data quality across large campaigns
Build reusable QA pipelines that reliably deliver high-quality data to pre-training teams for model training
Monitor and report on data quality over time, driving continuous iteration on quality standards, processes, and acceptance criteria
Qualification
Required
Strong engineering fundamentals with experience building data pipelines, QA systems, or evaluation workflows for pre-training data
Detail-oriented with an analytical mindset, able to identify failure modes, inconsistencies, and subtle issues that affect data quality
Solid understanding of how data quality impacts pre-training, with the ability to translate quality concerns into concrete signals, decisions, and feedback
Experience designing and validating automated quality checks, including rule-based systems, statistical methods, or model-assisted approaches such as LLM-as-a-Judge
Comfortable working autonomously, owning problems end-to-end, and collaborating effectively with researchers, engineers, and operations partners
Proficiency in Python and building ML / LLM workflows. Must be 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 with the ability to clearly articulate complex technical concepts across teams
Benefits
Comprehensive medical, dental, vision, life, and disability insurance.
Fully paid parental leave for all new parents, including adoptive and surrogate journeys.
Financial support for family planning.
Paid time off when you need it, relocation support, and more perks that optimize your time.
Lunch and dinner are provided daily.
Regular off-sites and team celebrations.
Company
Reflection
Reflection is a research lab making intelligence open and accessible for everyone to use, customize, and build on.
Founded in 2024
51-200 employees
Funding
Current Stage
Growth StageTotal Funding
$2.13BKey Investors
NVIDIACRV,Lightspeed Venture Partners,Sequoia CapitalCRV,Sequoia Capital
2025-10-09Series B· $2B
2025-03-07Series A· $105M
2025-03-07Seed· $25M
Leadership Team
Ioannis Antonoglou
Co-Founder, President & CTO
Recent News
2026-08-05
2026-08-04
Company data provided by crunchbase