Remote Senior Full-Stack AI Core Engineer

CIRCLE

Wilmington (DE)

On-site

USD 140,000 - 190,000

Full time

14 days+

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Benefits offered by this job

Equity grants

35 days PTO

Remote-only team

Job summary

Circle is seeking a strong full-stack engineer for the AI Core team to build AI-powered features using Ruby on Rails backend and React frontend. You will own end-to-end AI projects, from experimentation to production, including AI agents, RAG, and LLM-based tooling, in a remote, fast-paced environment.

Candidates should have 6+ years of full-stack experience, fluency in English, and hands-on production AI work.

Qualifications

/6+ years of full-stack engineering on high-traffic production apps.
/Proficiency in Ruby on Rails, MySQL/PostgreSQL, ReactJS.
/Hands-on experience building AI features in production (RAG, AI agents, LLM-powered tools).
/Strong experimentation mindset with designing & running A/B tests.
/Autonomy and collaboration in fast-paced ambiguous environments.
/English proficiency to CEFR C2 / ILR 5.

Responsibilities

/Ship full-stack AI projects end-to-end on Rails backend and React frontend.
/Design and run experiments (A/B tests, AI evaluations) to validate features.
/Build and integrate AI infrastructure components for production-grade inference.
/Improve processes and tools to scale AI features.
/Stay up-to-date with cutting-edge AI research and tools.
/Collaborate with leaders and designers during feature design.
/Prioritize speed of iteration while maintaining code quality and UX.