Circle Lead Engineer, AI Platform

Lead Engineer for AI Platform at Circle, $170K, remote, building LLM-powered agents. Requires 7+ years experience, Ruby on Rails/Python, eval infrastructure.

Join Circle as a Lead Engineer for our AI Platform. You will work on complex, tool-using systems with multiple tools, planning, orchestration, and sub-agents. Responsibilities include building and shipping production software, designing evaluation pipelines and datasets, and running experiments to improve AI agent performance.

- 7+ years of experience building and shipping production software, ideally including LLM-powered agents that take real actions in a product. - Worked on complex, tool-using systems (multiple tools, planning or orchestration, sub-agents), not just simple single-turn assistants. - Comfortable in Ruby on Rails / Python or ready to pick them up quickly. Python proficiency is a strong plus, especially for data and evaluation work. - Experience building evaluation or observability infrastructure for ML/AI systems, with frameworks like Braintrust, LangSmith, or similar. - Experience designing datasets, annotation workflows, or labeling pipelines for ML/AI evaluation. - Fast learner, experiment-driven, comfortable with ambiguity. - Proficient in English (spoken, written, reading) at CEFR Level C2 / ILR Level 5.

Salary: $170K per year Equity offered Work format: Remote (Anywhere in Europe, Middle East, Africa, Asia-Pacific)