Audio / Multimodal ML Engineer

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
• 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

• 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