About the role
TLDR: Audio / Multimodal ML Engineer to train and ship speech, audio and multimodal models for an AI safety platform that operates at 100M+ API calls/month.
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 and fine-tune large-scale audio and multimodal models from scratch and from pretrained checkpoints
Design and run experiments: architecture changes, data mixes, training recipes
Build and maintain audio data pipelines — from raw recordings to training-ready datasets
Optimize models for production: quantization, distillation, streaming inference
Deploy models end-to-end: from research checkpoint to low-latency serving
Collaborate with research to turn experimental ideas into shippable features
Define evaluation metrics and benchmarks that actually matter for the product
You’ll fit right in if you:
3+ years of experience training large-scale deep learning models in audio, speech, or acoustic domains
Strong hands-on experience with PyTorch, distributed training (DeepSpeed, FSDP, or similar)
Familiarity with audio/speech architectures (Audio Qwen, Whisper, HuBERT, Conformer, or similar)
Experience with vision-language and multimodal architectures (Audio Flamingo, Omni Qwen, or similar)
Track record of shipping models to production: you've hit latency targets, not just accuracy benchmarks
Comfortable working with large-scale audio data pipelines: preprocessing, augmentation, dataset curation
Understanding of audio signal processing fundamentals: spectrograms, mel features, noise reduction
Experience with SFT, DPO, GRPO or other alignment techniques — ideally in multimodal setting
Strong engineering fundamentals: clean code, version control, testing, documentation
Why White Circle
Salary of $100,000 to $250,000 + equity
Paid time off in line with your local regulations, no matter where you work from
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
Intro call with one of our colleagues
Сomplete the take-home assignment
Show your best during the technical interview
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
