Build evaluation infrastructure to measure AI system speed and accuracy — both offline (during development) and online (in production).
Create observability tooling and dashboards that surface quality metrics week-over-week.
Diagnose quality gaps. When accuracy drops, trace whether it's retrieval, ranking, prompting, or something else causing the issue.
Experiment with different models and agent configurations, using data to guide decisions.
Prototype and validate improvements to our RAG pipeline — chunking strategies, retrieval methods, re-ranking approaches.
Analyze how our customers are using our AI features to help us identify improvements or new areas for development.
Work closely with other engineers to give them confidence that their changes improve quality.
Help us stay up-to-date with the cutting-edge AI research, techniques, and tools.

Requirements

Experience building and evaluating AI systems in production — including RAG pipelines, search / retrieval systems, LLM-powered applications, and both offline and LLM-based evaluation frameworks.
Strong proficiency in Python for prototyping and experimentation.
Openness to learning Ruby on Rails — our production system is built in Rails, and you'll need to integrate with and instrument the existing codebase.
Comfortable building infrastructure and tooling (eval pipelines, dashboards, data processing).
Deep understanding of RAG architecture: chunking strategies, embeddings, retrieval, re-ranking, context management.
Strong experimentation mindset — you’re comfortable designing and running A/B tests, measuring results, and iterating quickly to discover what works and what doesn’t.
Strong data analysis skills — you can interpret results, identify patterns, and communicate findings clearly.
A desire to work in an environment which values speed of iteration and individual autonomy, while also embracing personal accountability and the ability to collaborate effectively as part of a dynamic team.
Comfortable in a fast-paced environment with a certain level of ambiguity, especially when learning and picking up new technologies when projects require it.
Strong alignment with our values, find our values on our career page if you haven’t read up on them yet.
You are proficient in English (spoken, written, and reading) at a CEFR Level C2 / ILR Level 5.

Benefits

Fully remote: work from anywhere in the world!
Autonomy and trust to do your job: we care about outcomes over everything else.
Paid time away: all employees are given 35 days of PTO annually. We also offer a paid sabbatical after 5 years.
Generous U.S. benchmarked compensation and startup equity no matter where you are in the world.*
Awesome medical coverage with 100% coverage for you and your family, or medical reimbursement options where applicable!*
Parental leave for parents expanding their family, or just starting one.
Home office stipend to help you get up and running.
Learning & development stipend to help you level up your professional skills.
Annual bonus potential for roles that don't already receive variable income or commission.
Company retreats: Twice a year, the Circle team gets together for a fully paid company retreat in incredible places around the world! We’ve had past retreats in Colombia, Portugal, and Mexico, with more planned on the horizon.

Applicant Tracking System Keywords

Tip: use these terms in your resume and cover letter to boost ATS matches.

Hard Skills & Tools

PythonRuby on RailsRAG pipelinessearch systemsretrieval systemsLLM-powered applicationsdata processingA/B testingdata analysischunking strategies

Soft Skills

experimentation mindsetcommunicationcollaborationpersonal accountabilityadaptabilityproblem-solvingteamworkautonomyspeed of iterationcomfort with ambiguity