Sepal AI specializes in PhD-level experts for AI model development. We provide robust, frontier data through a comprehensive process in sourcing, vetting, matching, trials, and peer quality control. We are currently working with the world's leading foundational AI model companies across domains in advanced sciences, professional services, and safety & preparedness.

About Sepal

Sepal is a data research company on a mission to advance human knowledge and capabilities through safe AI.
We partner with the world’s leading AI labs and enterprises to help their models get better at the tasks people actually want them to do.

We’ve built a Cloud-Native Agent Dataset Factory which turns the process of generating evaluation and training data from manual, inconsistent, and labor-intensive into something automated, standardized, and scalable.

Sepal AI was founded in 2024 by engineers and operators from Vercel and Turing. We went through Y Combinator, raised several million dollars from leading investors, and already count multiple Fortune 500s and top AI research labs as paying customers.

The Role

As a Software Engineer, you’ll build the full-stack applications and AI-enabled tooling that scale our data operations. Your work will directly empower the best AI teams in the world to build, test, and evaluate their most advanced models with unparalleled precision, speed, and safety.

You will work closely with research teams AND contribute to our core platform.

What You’ll Do

• Design and ship innovative web applications and internal tools that power our dataset factory.
• Build reliable APIs and backend services to manage data pipelines at scale.
• Collaborate with product, research, and data ops teams to turn complex workflows into intuitive user experiences.
• Help shape the architecture and best practices of our core engineering stack.

What We’re Looking For

• You’ve built something difficult and meaningful.
• 3+ years of professional software engineering experience.
• Ability to ship high-quality code quickly and iterate fast.
• Strong instincts for product design and user experience.

Bonus points if you have:

• Open-source contributions or a background in advanced science.
• Experience with reinforcement learning, ML/AI systems, or model annotation platforms.

Why Join Sepal?

• Work with the frontier: direct partnerships with the world’s top AI labs and enterprise AI teams.
• Competitive compensation with substantial equity.
• Rapid career growth opportunities and the chance to influence the future of AI development.
• Exceptional health, dental, and vision benefits.
• Flexible PTO and a culture designed around empowering productivity and creativity.
• A vibrant, collaborative team that pushes boundaries and values human expertise.

Our Tech Stack

We use TypeScript/Fastify, Python, TRPC, Next.js, and PostgreSQL in a monorepo. You don’t need to know them all, but you should be comfortable jumping into at least one.

○ Frontend Stack: Next.js (v13+), React, TypeScript ○ Backend Stack: Node.js, tRPC, Mikro ORM , PostgreSQL: ○ Infrastructure Stack: AWS/Fly.io/Vercel