About the Position

Research Engineer, Code RL (Reinforcement Learning)

San Francisco, CA | New York City, NY

About Anthropic

Anthropic’s mission is to create reliable, interpretable, and steerable AI systems. We want AI to be safe and beneficial for our users and for society as a whole. Our team is a quickly growing group of committed researchers, engineers, policy experts, and business leaders working together to build beneficial AI systems.

About the RL Teams

Our Reinforcement Learning teams play a critical role in advancing our AI systems. We've contributed to all Claude models, with significant impacts on the autonomy and coding capabilities of our latest Claude models. Our work spans several key areas:

Developing systems that enable models to use computers effectively
Advancing code generation through reinforcement learning
Pioneering fundamental RL research for large language models
Building scalable RL infrastructure and training methodologies
Enhancing model reasoning capabilities

We collaborate closely with Anthropic's alignment and frontier red teams to ensure our systems are both capable and safe. We partner with the applied production training team to bring research innovations into deployed models, and are dedicated to implement our research at scale. Our Reinforcement Learning teams sit at the intersection of cutting-edge research and engineering excellence, with a deep commitment to building high-quality, scalable systems that push the boundaries of what AI can accomplish.

About the Role

We're hiring for the Code RL team within the RL organization. As a Research Engineer, you'll advance our models' ability to write, edit, test, debug, and ship real software - end to end, on real codebases, with real tools - and to do it correctly, fast, and safely.

This role blends research and engineering. You'll design RL environments and coding tasks, build the reward signals and verifiers that capture what "good code" means, run training experiments on frontier models, diagnose why a model does (or doesn't) get better at a class of software-engineering work, and improve the speed and reliability of the pipelines that make all of that iterate fast. Code RL spans several focus areas - from agentic coding behaviors and code correctness, to long-horizon autonomous engineering, to high-performance code for accelerators - and we'll match you to the area where you'll have the most impact.

You may be a good fit if you:

Have strong software-engineering skills and deep Python expertise, including async/concurrent programming
Are comfortable owning systems end to end and debugging across the stack
Can balance research exploration with engineering implementation, and engage rigorously in shaping experimental design and interpreting results
Care about code quality, testing, and performance
Are passionate about the potential impact of AI and are committed to developing safe and beneficial systems

Strong candidates may also have:

Experience with reinforcement learning, RLHF, post-training, or LLM finetuning
Built coding agents, code-execution sandboxes, eval harnesses, verifiers, or developer tooling
Background in program analysis, testing, verification, compilers, or formal methods
Experience with PyTorch and large-scale distributed training; performance profiling and optimization of ML systems
CUDA / GPU or TPU kernel experience and accelerator-performance intuition
Experience with virtualization and sandboxed code execution environments

Related roles

If your background leans toward one of these areas specifically, you may also want to look at these postings:

Research Engineer, Performance RL (Reinforcement Learning) - teaching Claude to write correct, fast code for accelerators
Research Engineer, Universes - long-horizon, ultra-realistic agentic training environments
Research Engineer, Cybersecurity RL (Reinforcement Learning) - RL for security-relevant coding capabilities

We Offer

Competitive Salary: $500,000-$850,000 USD annually
Location-based hybrid policy: Currently, we expect all staff to be in one of our offices at least 25% of the time. However, some roles may require more time in our offices.
Visa sponsorship: We do sponsor visas! However, we aren't able to successfully sponsor visas for every role and every candidate. But if we make you an offer, we will make every reasonable effort to get you a visa, and we retain an immigration lawyer to help with this.

About the Company

Anthropic is a public benefit corporation headquartered in San Francisco. We offer competitive compensation and benefits, optional equity donation matching, generous vacation and parental leave, flexible working hours, and a lovely office space in which to collaborate with colleagues.

How we're different

We believe that the highest-impact AI research will be big science. At Anthropic we work as a single cohesive team on just a few large-scale research efforts. And we value impact - advancing our long-term goals of steerable, trustworthy AI - rather than work on smaller and more specific puzzles. We view AI research as an empirical science, which has as much in common with physics and biology as with traditional efforts in computer science. We're an extremely collaborative group, and we host frequent research discussions to ensure that we are pursuing the highest-impact work at any given time. As such, we greatly value communication skills.

The easiest way to understand our research directions is to read our recent research. This research continues many of the directions our team worked on prior to Anthropic, including: GPT-3, Circuit-Based Interpretability, Multimodal Neurons, Scaling Laws, AI & Compute, Concrete Problems in AI Safety, and Learning from Human Preferences.

Research Engineer, Code RL (Reinforcement Learning)

Job description