Staff Research Engineer - Frontier AI and Reinforcement Learning - US and Canada

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

• Rate: $57/hr
• Hours: 40 hours / week
• Experience: 5 - 10 years
• Location: Jersey City, NJ, USA + 1 more

Advance frontier AI through research and engineering across synthetic and agentic data, reinforcement learning, post-training, model understanding, benchmarks and evaluation. You will investigate high-impact questions, build research-grade prototypes and help turn validated findings into scalable AI systems.

WHAT YOU WILL DO

• Investigate frontier-model capabilities, limitations and training methods, formulate research questions and explore new approaches.
• Build research datasets, experiments, prototypes, tooling and evaluation frameworks. Train, test and evaluate models using modern ML tools.
• Analyze results with scientific rigor, data quality, reproducibility and evidence-based interpretation. Iterate from hypotheses to validated insights.
• Collaborate across Research, Engineering, Product and Operations to translate findings into practical systems.
• Communicate findings through technical reports, publications, open-source work and research forums where appropriate. Contribute through peer review, mentorship and technical leadership.

WHAT YOU WILL BRING

• 7+ years of professional experience with significant research engineering experience in machine learning or frontier AI systems.
• A PhD or master's degree in AI, machine learning, computer science or a closely related technical field, or exceptional equivalent research experience.
• Strong ML foundations and experience designing experiments, training or evaluating models, or developing AI systems.
• Research experience in at least one of synthetic or agentic data generation, reinforcement learning or post-training, model understanding, AI evaluation, benchmarks, or tool-using AI agents.
• Strong Python programming and experience implementing, testing and iterating with modern ML frameworks and tooling.
• Scientific judgment, rigorous reproducible methods and attention to data quality.
• Strong written and verbal communication, independent work and effective cross-functional collaboration.
• Experience mentoring engineers or researchers and providing technical leadership.

PROJECT DETAILS

Expected project length is three months, with an immediate start. Availability of at least 40 hours per week, 8 hours per day and four hours of daily Pacific Time overlap is required. Selection includes an approximately 20-minute client AI interview and a 45-60-minute technical delivery interview. Include your LinkedIn profile URL in your required resume.

LOCATION AND COMPENSATION

This remote opportunity is open to candidates in the United States and Canada at $57 USD per hour.

Company: Staff Research Engineer - Frontier AI and Reinforcement Learning - US and Canada
Location: Canada