Staff Research Engineer: Frontier AI & RL Innovator

Braintrust; United States; Remote; USD 65,000 - 92,000; Full time

Job summary

Braintrust seeks a Staff Research Engineer focused on frontier AI and reinforcement learning. You will advance research-engineering efforts across synthetic data, RL methods, post-training, model understanding and evaluation, building scalable prototypes and systems.

You will collaborate with Research, Engineering, Product and Operations, mentoring engineers and contributing to rigorous scientific results and publications where appropriate.

Qualifications

• 7+ years of professional experience in research engineering for ML or frontier AI systems.
• PhD or Master’s in AI/ML/CS or closely related field, or exceptional equivalent experience.
• Strong ML foundations, design of experiments and evaluation of models.
• Research experience in synthetic/agentic data generation, RL, post-training, model understanding or AI evaluation.

Responsibilities

• Investigate frontier-model capabilities and training methods; formulate research questions and explore new approaches.
• Build datasets, experiments, prototypes, tooling and evaluation frameworks; train, test and evaluate models.
• Analyze results with rigorous, reproducible methods and derive validated insights.
• Collaborate across Research, Engineering, Product and Operations to translate findings into practical systems.
• Communicate findings through technical reports, publications and open-source work, and provide mentorship and technical leadership.

Skills

ML research

Python programming

Mentoring

Cross-functional collaboration

Scientific judgment

Strong communication

Experience leading teams

Education

PhD or Master’s in AI/ML/CS or related field

Job description

Braintrust seeks a Staff Research Engineer focused on frontier AI and reinforcement learning. You will advance research-engineering efforts across synthetic data, RL methods, post-training, model understanding and evaluation, building scalable prototypes and systems.

You will collaborate with Research, Engineering, Product and Operations, mentoring engineers and contributing to rigorous scientific results and publications where appropriate.