About Circle

Circle is building the world’s leading all-in-one platform for online communities, powering creators, coaches, educators, and brands to connect their audiences through discussions, live streams, events, courses, and payments — all under their own brand.

We’re a fully remote team of 200+ people across 30+ countries, united by the mission to help creators build meaningful digital communities. We operate with trust, autonomy, and high expectations — and twice a year, we gather in stunning global locations for company offsites (think Portugal, Mexico, Thailand, Italy, and more).

The Role

We’re hiring a Lead Full-Stack Engineer to join our Applied AI team, which is pioneering the use of large language models (LLMs) to transform how creators interact, learn, and build on Circle.

You’ll lead a small, fast-moving team of engineers and ship full-stack AI projects — from building AI agents and retrieval-augmented systems to designing internal tools and scalable AI infrastructure. Your focus: experimentation, iteration, and real-world deployment of AI features that meaningfully improve user experience.

This is an opportunity to shape the future of AI-driven community platforms at scale.

What You’ll Do

• Ship end-to-end AI projects across Circle’s Ruby on Rails backend and React frontend.

• Design and run experiments, including A/B testing and AI evals to measure feature impact.

• Build and optimize infrastructure for LLM inference and fine-tuning.

• Scale production-ready AI features with performance and reliability in mind.

• Manage and mentor a team of 3 engineers while growing the Applied AI organization.

• Stay current on AI research and help integrate cutting-edge methods into real products.

• Work directly with Circle’s leadership and design teams to shape the product roadmap.

What You’ll Bring

• 7+ years building complex full-stack web applications (100k+ rpm scale).

• Strong experience in Ruby on Rails, ReactJS, and PostgreSQL/MySQL.

• Proven ability to lead engineering teams in growth-focused environments.

• A deep experimentation mindset — you move fast, test ideas, and learn quickly.

• Comfort working in fast-paced, high-autonomy environments.

• Excellent written and verbal communication (English C2 level).

• Bonus: Experience building and deploying AI-driven applications or backend systems for LLMs.

Compensation & Benefits

💰 $180,000 – $220,000 USD + equity

🌍 Fully remote (work from anywhere)

🏖 35 days PTO annually + paid sabbatical after 5 years

💻 Home office & learning stipends

🏥 100% medical, dental, and vision coverage (where applicable)

👶 Parental leave

✈️ Global company retreats twice a year

🎯 Startup-level autonomy, trust, and high-impact work

Apply

Join Circle and help build the next generation of community-driven, AI-powered software.

Apply at: circle.so/careers