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Chegg - Senior Software Engineer - AI/LLM Agents

Chegg
7 - 10 Years
Others

Posted on: 23/06/2026

Job Description

ABOUT THE ROLE :

We are looking for a Senior Engineer to join our AI team at the intersection of evaluation science, post-training, and foundation model development. You will own our end-to-end eval and benchmarking infrastructure the critical feedback loop that drives every major model improvement while contributing hands-on to post-training pipelines for industry-specific vertical foundation models.

This role is ideal for someone who has worked directly inside an LLM lab and understands what rigorous evaluation looks like at scale : designing the taxonomy of skills being measured, identifying failure modes, engineering synthetic data to close capability gaps, and translating eval signals into actionable training decisions.

WHAT YOU'LL DO :

Evaluation & Benchmarking :

- Design and own task-level evaluation frameworks for LLM agents and base models, covering multi-step reasoning, tool/API use, instruction following, and domain knowledge grounded in real user failure modes rather than off-the-shelf benchmark suites.

- Build comparative benchmarking pipelines to assess leading frontier models (GPT-4o, Gemini, Claude, Llama, Mistral, etc.) against each other and against internal models, with structured analysis of where each model family fails, regresses, or excels across subjects, topics, and task types.

- Produce capability gap reports that quantify performance deltas across dimensions such as subject-matter accuracy, reasoning depth, factual consistency, and refusal behaviour.

- Track model version regressions across provider releases to maintain a living competitive intelligence benchmark.

- Develop domain-specific benchmarks tailored to vertical use-cases (e.g., STEM tutoring, legal, finance, healthcare) including problem taxonomy design, rubric definition, and inter-annotator agreement pipelines.

- Define and drive synthetic data generation strategies to systematically address model shortcomings in specific subjects, topics, and skill areas :

1. Identify low-performance clusters from eval results and translate them into targeted data generation prompts and pipelines.

2. Design LLM-assisted pipelines for generating high-quality, diverse, and verifiable synthetic training and evaluation data at scale.

3. Validate synthetic data quality through auto-eval, human review, and downstream model performance lift experiments.

- Build automated regression suites integrated into CI/CD workflows to detect capability degradation across fine-tuning runs and model updates.

- Partner with product, curriculum, and research teams to translate eval insights into prioritized post-training and data flywheel decisions.

Post-Training & Fine-Tuning :

- Lead or directly contribute to SFT, RLHF, RLAIF, and DPO training runs on industry-specific vertical foundation models from dataset design through training execution and eval-gated release.

- Curate and engineer high-quality instruction-tuning and preference datasets for domain adaptation, with hands-on experience distinguishing signal from noise in annotation pipelines.

- Define data quality criteria, rejection sampling strategies, and deduplication pipelines for SFT corpora.

- Design preference pair construction methodologies and reward model training setups grounded in domain-specific quality rubrics.

- Implement and experiment with alignment techniques including reward modelling, process reward models (PRMs), and constitutional/RLAIF approaches.

- Run ablation studies and controlled experiments to attribute model behaviour changes to specific data or training interventions not just report final numbers.

- Contribute to continual pre-training and domain-adaptive fine-tuning pipelines for vertical models, including domain data sourcing, mixing strategies, and curriculum design.

Infrastructure & Tooling :

- Build scalable eval pipelines that run automatically on every training checkpoint and integrate into CI/CD for continuous model quality tracking.

- Maintain model cards, eval leaderboards, and internal dashboards providing visibility across experiments for both technical and non-technical stakeholders.

- Ensure reproducibility through rigorous experiment tracking (W&B, MLflow, or equivalent), versioned datasets, and documented training configs.

WHO YOU ARE :

Required :

- 5+ years of ML/AI engineering experience, with at least 23 years focused on large language models.

- Lab pedigree : Direct, hands-on experience at an LLM lab, AI research organization, or equivalent frontier AI team you have shipped models, not just called APIs.

- Familiarity with the full model lifecycle : pre-training data, post-training alignment, eval, and production deployment.

- Deep practical expertise in post-training methods :

1. SFT, RLHF, RLAIF, DPO, PPO from dataset construction through training and eval-gated release.

2. Experience with reward modeling, preference data curation, and quality control for alignment pipelines.

- Demonstrated experience designing LLM evaluation frameworks beyond standard benchmarks including task-level evals for agentic or multi-step workflows.

- Hands-on experience building synthetic data generation pipelines to address specific model capability gaps :

1. Designing targeted generation prompts based on eval failure analysis.

2. Validating synthetic data quality through downstream model performance experiments.

- Proven track record of comparative benchmarking across leading foundation models, with structured analysis of capability shortcomings by subject, skill, or task type.

- Experience training or fine-tuning vertical/industry-specific foundation models domain data curation, continual pre-training, or domain-adaptive SFT.

- Strong software engineering fundamentals : Python, PyTorch or JAX, distributed training.

Preferred :

- Publications or applied research contributions in LLM evaluation, alignment, or post-training.

- Experience with multi-modal models or agents with external tool/API use.

- Exposure to red-teaming, adversarial evaluation, or safety benchmarking.

- Model distillation, speculative decoding, or inference optimization experience.

- Prior experience in an education, STEM, legal, biomedical, or enterprise software vertical.

WHAT SUCCESS LOOKS LIKE :

30 Days :

Fully onboarded into training infra and eval repos. Running existing benchmarks end-to-end and producing a written gap analysis identifying missing coverage.

60 Days :

Shipped at least one new domain-specific benchmark and one synthetic data generation pipeline addressing a known model gap. CI-integrated eval running on every checkpoint.

3 Months :

Standardize model evaluation framework for foundation models. Own golden dataset strategies for fine-tuning with measurable subject-accuracy gains.

6 Months :

Recognized internally as the authority on model quality and competitive benchmarking. Eval insights are directly driving roadmap prioritization.

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