Wanted: Frontend Engineer to help us keep LLMs under control.

About us

White Circle is an AI Safety company building the safety, reliability, and optimization layer for AI systems. At the core of our platform are policies – simple natural-language rules that define what an AI model should and shouldn’t do. We automatically test, enforce, and continuously improve these policies at scale.

• We’ve raised $11M from top funds, founders, and senior leaders at OpenAI, Anthropic, HuggingFace, Mistral, DeepMind, Datadog, Sentry, and others
• We process over one hundred million API calls every month
• We fine-tune and train our own LLMs so they run faster and cheaper than any open or proprietary model

We’re a small, highly focused team. If you want to work deeply on hard problems, see your work ship to production quickly, and influence how AI safety is actually built – you’re the one we need.

You’ll fit right in if you:

• Know your way around TypeScript, React, Next.js, Tailwind.
• Have worked with LLMs (OpenAI API, function calling, context management — you get it).
• Can write non-trivial SQL without Googling “group by in window function explained.”
• Care about design, usability, and performance, not just “making it work.”

You will:

• Own and ship end-to-end product features across the full stack, from architecture and implementation to deployment and iteration.
• Design intuitive, high-quality user experiences, building seamless flows from onboarding to advanced analysis.
• Collaborate closely with founders, product, design, ML, and research to turn complex AI capabilities into accessible, reliable products.
• Drive the full development lifecycle and contribute to technical direction, product strategy, and engineering culture.

Why White Circle

• Salary of $80,000 to $150,000 + equity
• 20 days of paid vacation
• Work from Paris (hybrid) + relocation package
• Best medical insurance in France
• All the hardware, tools, and services you need
• Covered subscriptions for AI agents and IDEs
• Team off-sites twice a year: we’ve recently been to the Alps and to Saint-Tropez

How we hire

1. Intro call with one of our colleagues
2. Complete the take-home exercise
3. Show your best during the technical interview
4. Final call with our CEO and CTO

Please submit your application in English - it’s our company language so you’ll be speaking lots of it if you join