AI Engineer

Wanted: AI engineer who will 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 will:

• Train LLMs and VLMs using distributed frameworks (Megatron, DeepSpeed, etc.).

• Design and implement Mixture-of-Experts architectures for efficient scaling.

• Build multimodal training pipelines that handle text, images, and audio.

• Write custom Triton kernels to optimize training bottlenecks.

• Experiment with new architectures, hyperparameters, and data mixtures.

You’ll fit right in if you:

• Have fine-tuned models.

• Know the ins and outs of distributed training: tensor parallelism, pipeline parallelism, expert parallelism, ZeRO, FSDP.

• Can write Triton kernels to speed up attention, MLP layers, or custom ops.

• Have worked with multimodal architectures (Llava-style, Flamingo-style, or similar).

• Care about training stability, convergence, and squeezing maximum performance from hardware.

Why White Circle

• Salary of $100,000 to $250,000 + 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. Show your best during the technical interview

3. Opt: complete the take-home assignment

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