Backed by Accel, Index and Y Combinator.
About the role
As a Staff Software Engineer, RL Environments, you'll own the technical foundation for how Scale builds, runs, verifies, and delivers RL environments at scale.
What they're looking for
- 8+ years of software engineering experience with strong fundamentals in distributed systems, system design, data structures, and algorithms
- Strong Python skills and a track record of shipping production software, comfort in at least one other part of the stack (TypeScript/React, Go, Rust, or similar)
- Deep experience with containerization and sandboxed execution, including Docker, VMs, gVisor/Firecracker, Kubernetes, or equivalent
- Experience building or operating high-throughput backend systems: orchestration, job scheduling, queuing, and large-scale data pipelines
- Hands-on experience building with LLMs including agent loops, tool calling, MCP, or eval harnesses, and enough intuition about model behavior to reason about what a training signal actually teaches
- Demonstrated ability to own ambiguous, undefined problems end to end and drive them to a shipped system
More about this role
At Scale, our mission is to develop reliable AI systems for the world's most important decisions. Our products provide the high-quality data and full-stack technologies that power the world's leading models, and help enterprises and governments build, deploy, and oversee AI applications that deliver real impact.
Scale Frontier Data is the organization behind the training and evaluation data that frontier labs depend on. We build the systems, tooling, and expert workflows that turn hard human expertise into signals that models can learn from, across reasoning, coding, agentic tool use, and domain expertise.
Reinforcement learning environments are now the center of gravity for that work: the difference between a model that demos well and a model that reliably completes long-horizon work is almost always the quality of the environments and reward signals it was trained against.
As a Staff Software Engineer, RL Environments, you'll own the technical foundation for how Scale builds, runs, verifies, and delivers RL environments at scale.
An RL environment is a real piece of software: a containerized world with real dependencies, real state, real tools, and a grader that has to be...
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