LLM Research Scientist (Pre-training & Post-Training) @ Mercor

Hatch
Hatch

Software Engineering, Data Science

Australia

USD 100-120 / hour

Posted on Jul 15, 2026

We're looking for experienced machine learning researchers with hands-on experience training and improving language models end-to-end. You'll work on well-scoped empirical open-ended LLM research problems.

Pay for this job is USD $100-$120 per hour, which is approx. AUD $140-$170. It will be subject to exchange rates.

Responsibilities

  • Train transformer-based language models from scratch and fine-tune open-weight models.
  • Get the most out of limited data and compute.
  • Construct training corpora from raw web-scale sources.
  • Build post-training pipelines.
  • Diagnose and resolve training issues.

Requirements

We are looking for candidates with strong expertise in one or more of the following areas:

Foundation Model Pre-training

Experience With:

  • Training transformer-based language models from scratch, end-to-end.
  • Data- and compute-constrained regimes: allocating a fixed budget across model size, tokens, and epochs.
  • Diagnosing optimisation failures, convergence issues, and training instabilities.

Pre-training Data

Experience With:

  • Corpus construction from raw web crawls and other large unfiltered sources.
  • Data filtering, deduplication, quality classification, and mixture/ordering optimisation.
  • Measuring data interventions rigorously.

LLM Post-Training

Hands-on Experience With One Or More Of:

  • Supervised fine-tuning, including building your own datasets via synthetic generation, noisy or weak supervision, and rejection sampling.
  • Preference optimisation (DPO, RLHF, RLAIF) and reward modelling / human-preference prediction.
  • Alignment fine-tuning: shaping refusal behaviour, truthfulness, and unbiased reasoning while preserving general capability.
  • Fine-tuning for narrow, verifiable domains (math, code, games, structured prediction) where outputs can be checked programmatically.

Additional Areas Of Interest

Experience in any of the following is a plus:

  • Scaling laws and training-efficiency research.
  • Curriculum learning and data ordering.
  • LLM evaluation: benchmark construction, contamination control, statistically sound comparisons.
  • Reinforcement learning for language models.
  • Model alignment and AI safety.

General Qualifications

  • 3+ years of machine learning research experience (PhD research counts toward this requirement).
  • Strong experience with PyTorch, JAX, TensorFlow, or similar ML frameworks.
  • Degree from a top-100 university, experience at a FAANG or comparable AI company, or an equivalent research track record through publications or impactful open-source contributions.

Why Join

  • Work on cutting-edge foundation model research.
  • Collaborate with leading AI researchers on challenging, high-impact projects.
  • Flexible, project-based work with competitive compensation.

We consider all qualified applicants without regard to legally protected characteristics and provide reasonable accommodations upon request.

Contract and Payment Terms

  • You will be engaged as an independent contractor.
  • This is a fully remote role that can be completed on your own schedule.
  • Projects can be extended, shortened, or concluded early depending on needs and performance.
  • Your work at Mercor will not involve access to confidential or proprietary information from any employer, client, or institution.
  • Payments are weekly on Stripe or Wise based on services rendered.
  • Please note: We are unable to support H1-B or STEM OPT candidates at this time.

🟢 Please consider applying even if you don't meet 100% of what’s outlined 🟢

Key Responsibilities

  • 🔄 Training language models
  • 💻 Optimizing data usage
  • 🏗️ Building training pipelines

Key Strengths

  • 🧠 Machine learning research experience
  • ⚙️ Experience with ML frameworks
  • 📚 Foundation model pre-training
  • 📈 Scaling laws and training-efficiency research
  • 📊 Curriculum learning and data ordering
  • 🔒 Model alignment and AI safety

Why Mercor is partnering with Hatch on this role. Hatch exists to level the playing field for people as they discover a career that’s right for them. So when you apply you have the chance to show more than just your resume.

A Final Note: This is a role with Mercor not with Hatch.