Member of Technical Staff, Pretraining Data

Speedrun Talent Network; San Francisco (CA); On-site; USD 300,000 - 400,000; Full time

Benefits offered by this job

Equity grant

Competitive benefits

Job summary

Mirendil is a tech-first company advancing frontier AI R&D by building in-house models and running end-to-end experiments. You will set training data directions, run ablations, and supervise data pipelines that scale to trillions of tokens.

You’ll work with researchers on architecture and training runs, ensuring data quality, provenance, and reproducibility as the corpus grows. A base salary and meaningful equity are offered, with competitive benefits.

Qualifications

• Shipped a data change in a large pretraining run.
• Experience building data pipelines at scale (trillions of tokens).
• Proficient Python and ML framework tooling (PyTorch or JAX).

Responsibilities

• Build data pipelines for pretraining and manage code and docs.
• Improve data extraction, filtering, and deduplication of public data.
• Design ablations and data scaling experiments for model training.
• Coordinate with researchers to run experiments and evaluate results.
• Extend data mixtures to new scientific domains.
• Maintain data provenance and reproducibility as corpus grows.

Skills

Data pipelines

Python

Spark

Ray/Beam

PyTorch/JAX

Tools

Spark

Ray

Beam

Job description

Mirendil

Mirendil is a tech-first company focused on solving core bottlenecks that unlock step-change acceleration across science and technology. Our first goal is to democratize frontier AI R&D across scientific disciplines. We are building a frontier AI research company and training our own models end-to-end.

The Role

We pretrain our own models and we are scaling to larger models now. Agents handle much of the engineering, but deciding what goes into training still depends on strong human judgment.

You will set the direction for what our models train on and use agents to run the ablations, pipelines, and analyses that test it. You will work closely with the researchers who own architecture and training runs.

What You’ll Do

• Work on building data pipelines for pretraining, including repository-scale code and technical documents.

• Get more out of public data through better extraction, filtering, and deduplication of web pages, open-source code, and public datasets.

• Decide the data mixture for each run, and design the ablations and data scaling experiments that justify it.

• Direct agents to run those experiments and pipelines in parallel, and decide which results to trust.

• Extend a code-first mixture into scientific domains, starting from where our models fall short.

• Keep the corpus clean as it grows: provenance, decontamination against our evals, and reproducible versions.

About You

• You have shipped a data change into a large pretraining run and can show the ablation that justified it.

• You have built data pipelines at the scale of trillions of tokens with Spark, Ray, Beam, or similar, and you write strong Python.

• You know PyTorch or JAX well enough to run your own training experiments.

• You have hands-on experience with at least two of: deduplication, quality classifiers, mixture optimization, data scaling laws, or long-context and code data.

• You can tell when an experimental result is real, and you explain your reasoning clearly in writing.

If you’re excited about shaping what our models learn from, and proving it with experiments, we’d love to hear from you.

We offer a base salary of $300,000–$400,000 USD and a meaningful equity grant, depending on experience and background, along with competitive benefits.