Research Scientist​/Research Engineer

Collinear is a research-focused AI company building systems that make intelligent models more reliable, aligned, and useful in real-world settings. We work across post-training, RL, distillation, and evaluation to help teams get practical reasoning and behavior from open-source models. Our approach is grounded in technical rigor, clear thinking, and building tools that last.

We operate with very little bureaucracy, which means decisions are made quickly and ideas move straight into action. Everyone has real ownership and is trusted to learn fast, ask questions, and figure out how to unblock themselves when the path is not obvious. We expect clear communication, thoughtful judgment, and a focus on impact rather than process. You will work closely with teammates who care deeply about the craft and the mission.

People who enjoy solving hard problems, take initiative, and do not need hand holding tend to thrive  you like autonomy, fast decision cycles, and collaborating with others who hold a high bar for clarity and execution, you will feel at home here. This is a place for builders who want their work to matter and to be felt immediately.

Comprehensive medical, dental, and vision coverage

10 company holidays and flexible PTO to rest, recharge, and take care of personal needs

12 weeks of paid parental leave for all new parents

Class Pass membership for fitness, wellness, and recovery

Regular in-office lunches to make your day smoother

Team-driven events, lunches, and opportunities to connect

Conference support for employees with published papers

Close collaboration with founders, research scientists, and engineering leads

High-impact ownership across projects, features, and research areas

Exposure to advanced LLM evaluation, post-training workflows, and emerging techniques for improving model performance

Startup environment where your work directly shapes the company

Competitive base salary tailored to your experience and scope of impact

Meaningful equity ownership for full-time team members

Relocation bonuses for candidates moving to join the team

Work with us

At Collinear, we're revolutionizing how enterprises deploy and scale AI safely and reliably. If this resonates with you, we’d love to connect.

Sunnyvale, California

Full time

Research

At Collinear
, we help teams fearlessly ship AI.

Frontier labs and AI-native companies use our Sim Lab to find capability gaps in their agents and generate high-quality data to close them. We believe that the next generation of AI progress won't come from just bigger models, but from more rigorous, long-horizon simulation and programmatic verification.

Sim Lab allows researchers to spin up realistic environments, run agents through complex tasks, and surface failure modes under real-world conditions. We then close the loop by generating targeted synthetic data to retrain models, delivering measurable quality lift on the metrics that actually matter.

We are looking for Research Scientists and Research Engineers to help us build the data engine for frontier AI. In this role, you will bridge the gap between frontier research and production engineering. You will develop the high-fidelity environments and evaluation stacks that the world’s leading AI labs rely on to stress-test their most advanced agents. Your work will involve iterating on novel RL approaches and translating them into robust, scalable infrastructure that moves the needle on real-world model metrics.

Build Agentic Environments: Design and implement the next generation of "Sim Labs", ultra-realistic, long-horizon simulation environments where agents learn to navigate ambiguity and maintain context.

Programmatic Verification: Develop rigorous, policy-aware judges and evaluations that measure genuine capability and safety beyond simple benchmarks.

Close the Loop: Design and execute high-quality post-training runs (CPT, SFT, RL) to deliver frontier performance on open-source models using curated, high-signal data.

Rapid Iteration: Debug and iterate across the full ML stack, from infrastructure to model behavior, ensuring our tools remain "command-line first" and developer-friendly.

Collaborate: Work daily with the founders and research staff to shape the roadmap and push the state-of-the-art in AI reliability.

We are looking for individuals who demonstrate a rare combination of technical depth, research intuition, and high agency.

Technical Foundation: A Bachelor’s, Master’s, or PhD in a technical field (CS, Math, Physics, etc.), or a demonstrated "proof of work" through significant open-source contributions or industry experience.

Engineering Rigor: A strong foundation in software engineering with the ability to build robust, scalable infrastructure. You should be comfortable in a Python-friendly, CLI-first development environment.

ML Fluency: A principled…