Who you are

• 6+ years of experience in software engineering, data science, or ML — with a foundation in areas like search/retrieval, information extraction, NLP, or recommendation systems before transitioning to LLM-powered applications
• 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
• Experience with evaluation frameworks (Braintrust, LangSmith, or similar)
• If you're excited about making AI systems work reliably at scale, this is for you

What the job involves

• The Applied AI team at Circle is at the forefront of leveraging AI to drive innovation for our customers through transformative applications of large language models (LLMs)
• We build AI-powered features for our customers — AI agents, AI workflows, and AI copilot
• As we scale these features to more customers, we're investing in robust infrastructure for measuring, diagnosing, and improving AI system speed and performance
• We're looking for a strong AI Platform Engineer to help establish the foundation for this layer
• This is a new focus area for us, with this being the first AI platform engineer hire at Circle. You’ll have significant ownership in shaping how we approach it
• This role focuses on production AI systems — building infrastructure to measure and improve them— rather than ML research or model training
• You'll build evaluation frameworks, observability tooling, and diagnostic infrastructure that tells us whether our AI systems are working well and helps identify where and how to improve them
• When you find gaps, you'll prototype solutions, validate them with data, and work with the team to implement these improvements
• 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
• We don't track hours, but we do manage for high expectations very closely. We collaborate across time zones, are highly async, and like to document a lot

Benefits

• Medical coverage & reimbursements: Depending on your location, you will either be offered a full medical plan for you & your family, or offered generous monthly reimbursements to help with medical costs
• Equity package: We offer an equity package to every person that works at Circle
• Paid time off: We offer 35-days of PTO per year based on your hire date. Up to 50% can carry over to the next year
• Work from home, or anywhere: All of our employees are 100% remote!
• Learning & development stipend: Take advantage of up to $500 USD per year to help you level up your professional skills
• Home office stipend: New joiners receive $2,150 USD on their first paycheck to help outfit their home office, with a refresh every three years
• Company offsites: Twice a year, the Circle team gets together for a fully paid company retreat in incredible places around the world!
• Annual bonus: Roles that don't already receive variable income or commission are eligible to earn up to an extra 5% of their annual earnings as a yearly bonus based on overall company performance
• 401k with employer match: U.S. employees can partake in a 401k plan that has a 5% match, dollar-for-dollar
• U.S.-benchmarked compensation, no matter where you are in the world
• Paid sabbatical: After 3 years of employment, team members earn a paid 1-month sabbatical to decompress and unwind
• Parental leave for parents expanding their family, or just starting one