Research Engineer, Intern – Benchmarking
At a glance
Junior AI Research role at Mercor. San Francisco · internship.
Pay not stated Research Engineer salary
aimlroles summary, based on the employer's posting.
What you'll do
- Build benchmarks for tool use, agent behavior and practical reasoning, keeping measures useful as training scales
- Run evaluation systems from model runs through scoring, dashboards and reports so teams can compare performance
- Inspect model mistakes, group failure patterns and measure their frequency to guide reward design and data curation
- Develop scoring rubrics and automated evaluators, balancing dependable judgments with scalable review
- Measure data quality against key benchmarks and use findings to steer data generation and curation
What you bring
- You have applied research experience focused on evaluating models, benchmarking them or analyzing failures
- You can code well and have hands-on experience with machine-learning models and evaluation code
- You understand algorithms, data structures and backend systems, and can work with APIs, databases and cloud platforms
- You can interpret model behavior, experiment results and data quality through evaluation and failure analysis
Who this fits
This is an internship for someone drawn to applied AI research and engineering work on model evaluation. You’ll work in person in San Francisco five days a week.
From the employer
About Mercor
Mercor's mission is to organize human intelligence to power the AI economy. We're a leading AI data company, building the layer between human expertise and frontier models. Millions of domain experts on the platform are paid over $4 million per day to train frontier AI models. Mercor's APEX benchmark family measures AI's real-world impact on professional work. Mercor Enterprise brings this same infrastructure to Fortune 500 companies: helping companies capture how their best people actually work, translating that expertise directly back into agents.
Mercor is creating a new category of work where expertise powers AI advancement. Achieving this requires an ambitious, fast-paced and deeply committed team. You’ll work alongside researchers, operators, and AI companies at the forefront of shaping the systems that are redefining society. Mercor is a profitable Series C company valued at $10 billion. We work in-person five days a week in our San Francisco, NYC, or London offices.
About the Role
As a Research Engineer at Mercor, you’ll work at the intersection of engineering and applied AI research. You’ll own benchmarking pipelines, evaluation systems, and failure analysis workflows that directly inform how we train and improve frontier language models.
Your work will define how we measure tool use, agentic behavior, and real-world reasoning. You’ll design and run evals, build rubrics and scorers, and turn failure analysis into actionable improvements for post-training, RLVR, and data pipelines.
What You’ll Do
Benchmarking: Design, implement, and maintain benchmarks and metrics for tool use, agentic behavior, and real-world reasoning; ensure benchmarks scale with training and stay aligned with product and research goals.
Evaluation systems: Build and operate LLM evaluation systems end-to-end runs, scoring, dashboards, and reporting, so researchers and applied AI teams can track model performance and compare runs at scale.
Failure analysis: Run systematic failure analysis on model outputs (e.g., wrong tool use, reasoning errors, safety/alignment issues); categorize failure modes, quantify prevalence, and feed findings into reward design, data curation, and benchmark design.
Rubrics and evaluators: Create and refine rubrics, automated evaluators, and scoring frameworks that drive training and evaluation decisions; balance rigor with scalability (human vs. model-as-judge, calibration, agreement).
Data quality and usability: Quantify data usability, quality, and impact on key benchmarks; use evals and failure analysis to guide data generation, augmentation, and curation.
Cross-team collaboration: Work with AI researchers, applied AI teams, and data producers to align evals with training objectives and to prioritize benchmarks and failure analyses that matter most.
Ownership in a fast-paced environment: Operate in a high-iteration research setting with strong ownership of benchmarks, evals, and failure-analysis workflows.
What We’re Looking For
Strong applied research background, with focus on model evaluation, benchmarking, and/or failure analysis.
Strong coding skills and hands-on experience with ML models and evaluation code.
Solid grasp of data structures, algorithms, and backend systems.
Comfort with APIs, SQL/NoSQL, and cloud platforms for running and storing eval results.
Ability to reason about model behavior, experimental results, and data quality from evals and failure analyses.
Excitement to work in person in San Francisco five days a week in a high-intensity, high-ownership environment.
Nice To Have
Industry experience on a post-training or evaluation/benchmarking team (highest priority).
Publications at top-tier venues (NeurIPS, ICML, ACL), especially in evaluation or benchmarking.
Experience building or running LLM evaluations, benchmarks, or failure-analysis pipelines.
Experience with synthetic data generation, rubric design, or RL-style workflows that use evals for reward shaping.
Work samples or code (e.g., eval frameworks, benchmark suites, failure-analysis reports or tooling) that demonstrate relevant skills.
Benefits
Health Benefits eligible at 30+ hours a week
Overtime eligible at 1.5x from 40 to 55 hours; 2x over 55 hours-week.
$1.5K monthly stipend for meals
Relocation & Housing Support
Free Equinox membership
$200 monthly laundry reimbursement
$200 monthly personal wellness reimbursement
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