Our Mission 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 …
Subject Matter Expert - Election Integrity, Violent Extremism, and Fraud
London, England, United Kingdom · On-site
SeniorVisa sponsorship$2.1B raised
Our Mission 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 …
Our Mission 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 …
Our Mission 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 …
San Francisco, California, United States · On-site
Entry levelVisa sponsorship$2.1B raised
Our Mission 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 …
Skills: Office management, Hospitality, Inventory management, Vendor coordination, Administrative support
Member of Technical Staff - Research Software Engineer - Safety Evaluations Infrastructure
London, England, United Kingdom · On-site
SeniorVisa sponsorship$2.1B raised
Our Mission 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 …
Our Mission 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 …
Skills: Strategic Communication, Reputation Management, Public Affairs, Media Campaigns, AI Policy
Our Mission 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 …
Skills: Data Engineering, Pipeline Design, Batch Processing, Streaming Workloads, Spark
Member of Technical Staff - Engineering Lead, Data Ingestion
London, England, United Kingdom · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Skills: Team Leadership, Web Crawling, Data Ingestion Pipelines, Data Lake Architecture, Distributed Computing
San Francisco, California, United States · On-site
SeniorVisa sponsorship$2.1B raised
Our Mission 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 …
Skills: Financial Modeling, Capital Allocation, Forecasting, Planning, Deal Economics
Our Mission 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 …
Member of Technical Staff - Engineering Lead, Compute Platform
London, England, United Kingdom · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Skills: Kubernetes, Multi-cloud Scheduling, Cluster Management, GPU Deployment, Systems Engineering
Our Mission 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 …
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Member of Technical Staff - Engineering Lead, Platform Foundations
London, England, United Kingdom · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Member of Technical Staff - Engineering Lead, Shared Services
London, England, United Kingdom · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Skills: Distributed Systems Design, Kubernetes, Container Orchestration, Engineering Leadership, Service Reliability
Member of Technical Staff - Engineering Lead, Applications
London, England, United Kingdom · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Skills: Engineering Leadership, Full-stack Engineering, Team Mentorship, System Architecture, React
San Francisco, California, United States · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
San Francisco, California, United States · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Skills: Enterprise Risk Management, Control Architecture, AI Governance, Regulatory Compliance, Risk Reporting
San Francisco, California, United States · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
Skills: Identity and Access Management, Zero Trust Architecture, OAuth 2.0, OIDC, SAML
San Francisco, California, United States · On-site
Senior+Visa sponsorship$2.1B raised
Our Mission 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 …
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Full-time
Salary, Equity, Stock Options, Medical Insurance, Dental Insurance, Vision Insurance
Visa sponsorship available
Posted 2d ago
~40 hrs/week
Responsibilities
Build systems to transform pre-trained models into aligned general agents through post-training research and engineering. Develop data pipelines, reward models, and RL algorithms to improve model reasoning and instruction following.
Requirements
Requires deep knowledge of ML fundamentals and practical experience with large-scale LLM training and distributed systems. Candidates must have a proven track record of owning ambitious research agendas that lead to measurable model improvements.
Full job description
Our Mission
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.
About the Role
Build systems that transform powerful pre-trained models into aligned and general agents.
Drive research and engineering initiatives that push the frontier of post-training, from data curation to large-scale optimization.
Develop data generation pipelines, reward models, reinforcement learning algorithms, and inference-time scaling techniques.
Collaborate across pre-training and post-training teams to deliver step-function gains in model capability.
Contribute to shaping our understanding of how large models learn to reason, follow instructions, and improve through reinforcement learning.
About You
Deep understanding of machine learning fundamentals and practical experience with large-scale LLM training.
Strong engineering skills, comfortable diving into complex ML codebases and distributed systems.
Experience improving model behavior through data, reward modeling, or RL techniques.
Evidence of owning ambitious research or engineering agendas that led to measurable model improvements.
Thrive in a fast-paced, high-agency startup environment; bias toward action and clarity of execution.
Able to work fluidly across research and infra boundaries
Strong communication capabilities and comfort working collaboratively
Passionate about advancing the frontier of intelligence.
What We Offer:
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.
Reflection is a research lab making intelligence open and accessible for everyone to use, customize, and build on. Our team previously built frontier LLMs at labs like DeepMind, OpenAI, and Anthropic. We believe AI should be built in the open, with transparent research and collaborative development. That means giving enterprises, governments, and sovereign entities true ownership and control of AI that performs at the highest level.
Our mission: make intelligence open and accessible to all.
Offices: 124 E 14th St, New York, NY 10003, US · 144 2nd St, San Francisco, California 94105, US · 221 Pentonville Road, London, England WC1X 9DJ, GB
Reflection is a research lab making intelligence open and accessible for everyone to use, customize, and build on. Our team previously built frontier LLMs at labs like DeepMind, OpenAI, and Anthropic. We believe AI should be built in the open, with transparent research and collaborative development. That means giving enterprises, governments, and sovereign entities true ownership and control of AI that performs at the highest level.
Our mission: make intelligence open and accessible to all.
Offices: 124 E 14th St, New York, NY 10003, US · 144 2nd St, San Francisco, California 94105, US · 221 Pentonville Road, London, England WC1X 9DJ, GB