# Research Engineer at AfterQuery

- Company: AfterQuery
- What the company does: AfterQuery captures how experts reason and turns real-world professional work into high-quality training data for frontier foundation models. Backed by Y Combinator.
- Company website: https://afterquery.com
- Type: Startups (AI role)
- Level: Mid level
- Location: San Francisco
- Work setup: On-site
- Pay: $210K to $450K base salary per year (USD)
- Posted: 2026-08-27
- Apply by: 2026-10-11
- Apply: https://jobs.ashbyhq.com/afterquery/ae665a77-b88d-418e-941a-6c3da870f052
- Page: https://www.1752.vc/careers/jobs/afterquery-research-engineer/

## About the role

As the Research Engineer, you will design and run training experiments that isolate the impact of our datasets on model behavior. Through controlled SFT and RL - base post-training experiments, you will measure how different data sources, structures, and selection strategies affect capability, generalization, and alignment. You will own the full experiment loop: formulate the hypothesis, build the pipeline, run the model, analyze the results, identify confounders, and determine what should happen next.

## What they're looking for

- At least 2 years of professional experience in machine learning engineering, research engineering, ML infrastructure, or a closely related field, 2-4+ years preferred
- Strong Python and software-engineering skills
- Hands on experience with PyTorch, JAX, Ray, and Slurm
- Experience building production-quality ML training, evaluation, or data infrastructure
- Hands-on experience with LLM fine-tuning, post-training, and evaluation
- Ability to build reliable, reproducible systems for launching and comparing ML experiments

Tags: Research