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San Francisco, California, United States
Onsite
Available
Reflection is a research lab making intelligence open and accessible for everyone to use, customize, and build on. We build open models that let anyone control their intelligence and help shape the future of AI. Our mission: make intelligence open and accessible to all.
The web is one of the most important sources of information for frontier AI systems. The quality, coverage, freshness, and diversity of web data directly influence model capabilities.
As a member of the Data Team, your mission is to build and operate large-scale web crawling systems that continuously discover, acquire, and process content from across the internet. You will own the infrastructure that powers web-scale data collection, from URL discovery and scheduling to distributed crawling, content extraction, and dataset delivery.
You will work directly with world-class researchers to understand which parts of the web matter most for model performance and build systems that efficiently acquire high-value content at scale.
This role is ideal for engineers who love building distributed systems, optimizing large-scale crawlers, and solving the unique technical challenges of collecting data from the modern web.
Working closely with our pre-training, infrastructure, and data quality teams, you will:
Build and operate web-scale crawling infrastructure capable of continuously collecting data across billions of URLs
Design and optimize URL discovery, prioritization, scheduling, and crawl orchestration systems
Develop distributed crawlers that efficiently acquire content while respecting site constraints and operational requirements
Build systems for content extraction, rendering, parsing, and normalization across diverse web formats
Improve crawl coverage, freshness, efficiency, and quality through measurement and experimentation
Design infrastructure for large-scale recrawling, change detection, and incremental updates
Develop specialized crawlers for high-value domains, dynamic websites, and difficult-to-access content sources
Analyze crawl performance and web coverage to identify gaps, inefficiencies, and opportunities for improvement
Build observability, monitoring, and reliability systems for large-scale crawl operations
Debug production issues and continuously improve the performance, scalability, and resilience of crawling infrastructure
Passionate about web-scale systems and the challenges of collecting information from the internet
Curious about how web data influences model capabilities and willing to iterate based on downstream results
Comfortable balancing crawl quality, coverage, freshness, and operational efficiency
Enjoy working at the intersection of distributed systems, data infrastructure, and AI
Able to collaborate closely with researchers, infrastructure engineers, and data quality teams
Experience building large-scale web crawling, search indexing, content acquisition, or internet-scale data collection systems
Strong understanding of crawling architectures, URL frontier management, scheduling, and distributed crawl coordination
Experience with large-scale distributed systems using technologies such as Ray, Spark, Beam, Flink, or similar frameworks
Familiarity with content extraction, HTML parsing, browser automation, rendering systems, and modern web technologies
Experience operating systems that process petabyte-scale datasets
Strong systems engineering skills, including reliability, observability, performance optimization, and debugging
Experience designing experiments and using data to improve crawl quality, coverage, and efficiency
Excellent communication skills and the ability to reason clearly about system tradeoffs and operational constraints
Experience building search engines, web indexes, or internet-scale crawling platforms
Familiarity with anti-bot systems, dynamic web content, browser automation, and large-scale extraction pipelines
Understanding of how web data is used in training and evaluating large language models
Experience with distributed storage systems, content deduplication, and web-scale dataset management
We believe that to make intelligence open and accessible to all, you need to start at the foundation. Joining Reflection means building from the ground up as part of a talent-dense team. You will help define our future as a company, and help define the future of open foundational models.
We want you to do the most impactful work of your career with the confidence that you and the people you care about most are supported.
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: We have regular off-sites, happy hours, and team celebrations.
Export Control Notice: 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 control laws, which may require the Company to seek government authorization.
Equal Employment Opportunity Statement
Reflection AI is an equal opportunity employer. We do not discriminate on the basis of race, color, religion, sex (including pregnancy), sexual orientation, gender identity or expression, national origin, ancestry, age, marital status, disability, genetic information, veteran or military status, or any other characteristic protected by applicable law. We encourage applicants from all backgrounds to apply.
We provide reasonable accommodations throughout the hiring process for applicants with disabilities, pregnancy-related limitations, or religious needs. If you need an accommodation, contact us at accommodations@reflection.ai.
We will consider for employment qualified applicants with arrest and conviction records in accordance with applicable law, including the San Francisco Fair Chance Ordinance and the California Fair Chance Act.
Candidate and Employee Privacy Notice: We collect and process personal data about applicants for the purposes described in our Candidate and Employee Privacy Notice