Senior Full-Stack Software Engineer, Applied AI

About the Company

Circle is building the world’s leading all-in-one platform for online communities. We make it possible for creators, coaches, educators, and businesses to bring together their audience with engaging discussions, live streams, events, chat, courses, and payments — all in one place, all under their own brand.

Responsibilities

• Ship full-stack AI projects end-to-end on a product built in Ruby on Rails backend and React frontend
• Design and run experiments including A/B tests and AI evaluations to validate features
• Build and integrate components for AI infrastructure and optimize for performance and reliability
• Improve processes, tools, and systems to scale AI features into production-ready solutions
• Stay up-to-date with cutting-edge AI research, techniques, and tools
• Work closely with leaders and designers throughout the feature design process

Requirements

• 6+ years of experience as a full-stack engineer on high-traffic production applications
• Strong proficiency in Ruby on Rails, MySQL / PostgreSQL, and ReactJS
• Hands-on experience building and shipping production AI features (RAG, AI agents, or LLM-powered tools)
• Strong experimentation mindset with experience in A/B testing and measuring results
• Proficiency in English at CEFR Level C2 or ILR Level 5
• Ability to work in a fast-paced, ambiguous environment

Benefits

• U.S.-benchmarked compensation globally
• Company equity with ongoing refresh grants
• 35 days of paid time off each year
• Remote-only work environment with biannual company retreats