RL Environment Engineer

About AfterQuery

AfterQuery builds the training data and evaluation infrastructure that frontier AI labs use to improve their models. We work with the world's leading labs to design high signal datasets and run rigorous evaluations that go beyond static benchmarks. We are a small, early team (post Series A) where individual contributors have a direct impact on how the next generation of models learns and improves.

The Role

As a SWE (Environments), you will design the datasets and evaluation rubrics that directly influence how frontier models learn. You'll work hands-on with research teams at top AI labs, experimenting with data-collection strategies, diagnosing model failure modes, and developing metrics to determine whether a model is actually improving. You'll go from hypothesis to live experiment quickly, and your output will feed directly into model training runs at scale.

Day to day, you will design data slices that expose meaningful failure modes across domains like finance, code, and enterprise workflows. You will build and refine reward signals for RLHF and RLVR pipelines. You will develop quantitative frameworks for measuring dataset quality, diversity, and downstream impact on alignment and capability. You will partner with lab research teams to translate their training objectives into concrete data and evaluation specifications.

Compensation is $200K base plus profit share of roughly 150% of base, bringing expected total cash to around $500K, plus competitive equity.

What You'll Do

Design data slices and explore data shapes that expose meaningful model failure modes across domains like finance, code, and enterprise workflows

Build and refine evaluation rubrics and reward signals for RLHF and RLVR training pipelines

Model annotator behavior and run experiments to improve different model capabilities

Develop quantitative frameworks for measuring dataset quality, diversity, and downstream impact on model alignment and capability

Create and manage both real-world and synthetic data pipelines

Partner with lab research teams to translate their training objectives into concrete data and evaluation specifications

Requirements

Must-Have

1–4 years of software engineering experience with strong technical depth

Genuine obsession with how data structure, selection, and quality drive model behavior

Ability to design lightweight experiments, move fast, and extract actionable insights from messy results

Comfort working across domains, finance, software engineering, policy, and more

Track record of shipping, bias toward building, not theorizing

Nice-to-Have

Prior work or internship at an RL environment company, AI safety org, or benchmarking org (METR, Artificial Analysis, or equivalent)

Former founder or early engineer at an early-stage startup

Experience building data pipelines (real-world + synthetic)

Familiarity with RLHF / RLVR training pipelines