Research Engineer Intern - AI Data & Model Evaluation

mercor.com; San Francisco (CA); On-site; USD 180,000 - 280,000; Full time

Benefits offered by this job

Health benefits

Overtime pay

Meals stipend

Relocation assistance

Housing support

Equinox membership

Laundry reimbursement

Wellness reimbursement

Job summary

Mercor is seeking a Research Engineer to join our in-person office-based teams in San Francisco, NYC, or London. You will work at the intersection of engineering and applied AI research, contributing to post-training, RLVR, synthetic data generation, and large-scale evaluation workflows that impact frontier language models.

You will help train large language models to master tool use, agentic behavior, and real-world reasoning in production environments, shaping rewards, running experiments, and

Qualifications

• Strong applied research background in ML/AI.
• Solid coding proficiency with ML models.
• Strong understanding of data structures and algorithms.
• Experience with backend systems and scalable software.
• Familiarity with APIs and SQL/NoSQL databases.
• Experience with cloud platforms.
• Ability to reason about model behavior and experiments.

Responsibilities

• Work on post-training and RLVR pipelines to understand data, rewards, and training strategies impact on model performance.
• Design and run reward-shaping experiments to improve LLM tool-use and reasoning.
• Quantify data usability, quality, and performance uplift on benchmarks.
• Build and maintain data generation and augmentation pipelines scalable to training needs.
• Create rubrics, evaluators, and scoring frameworks for training and evaluation decisions.
• Build and operate LLM evaluation systems, benchmarks, and metrics at scale.
• Collaborate with AI researchers, applied AI teams, and data-producing experts.
• Operate in a fast-paced research environment with rapid iteration and high ownership.

Skills

Applied research

Coding proficiency

Data structures

Algorithms

Backend systems

APIs

SQL/NoSQL

Cloud platforms

Model evaluation

Experimental design

Job description

Mercor is seeking a Research Engineer to join our in-person office-based teams in San Francisco, NYC, or London. You will work at the intersection of engineering and applied AI research, contributing to post-training, RLVR, synthetic data generation, and large-scale evaluation workflows that impact frontier language models.

You will help train large language models to master tool use, agentic behavior, and real-world reasoning in production environments, shaping rewards, running experiments, and