Multimodal ML Engineer

White Circle; Paris, France; Hybride; EUR 120 000 - 180 000; Plein temps

Avantages offerts par ce poste

Equity

Flexible time off

Hybrid work (Paris/London)

Relocation package for Paris

Medical insurance in France

Learning and development support

All hardware and tools provided

Team off-sites

Résumé du poste

White Circle is an AI Safety company building the safety, reliability, and optimization layer for AI systems. You will train and fine-tune large multimodal models across vision, audio, and language, and extend models with new modalities while designing experiments and synthetic data pipelines.

You will optimize production inference, build alignment pipelines (SFT, DPO, reward modeling), and contribute to scalable systems using PyTorch, DeepSpeed, and MoE architectures.

Qualifications

• Experience training large-scale multimodal models (vision-language, audio, speech)
• Hands-on with RLHF/alignment for multimodal data
• Shipping models to production with latency targets

Connaissances

Multimodal training

PyTorch

Distributed training

RLHF/alignment

Model deployment

Data curation

MoE architectures

Video/audio modeling

Outils

PyTorch

DeepSpeed

FSDP

MoE frameworks

Description du poste

About us

White Circle https://whitecircle.ai/ 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 100M+ 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 multimodal models (vision-language, audio, speech) from scratch and from pretrained checkpoints
• Extend models across modalities: image understanding, video temporal modeling, long-context processing, and streaming audio
• Design and run experiments: architecture changes, data mixes, training recipes
• Build and maintain multimodal data pipelines - from raw images, video, and audio recordings to training-ready datasets, including synthetic data generation
• Train and optimize MoE architectures for efficient multimodal inference
• Build alignment pipelines: SFT, DPO, GRPO, reward modeling - across modalities, not just text
• Optimize models for production: quantization, distillation, batching, streaming and low-latency serving
• Deploy models end-to-end: from research checkpoint to production serving
• Define evaluation metrics and benchmarks that actually matter for the product: visual QA, spatial reasoning, video comprehension, speech and audio understanding

You'll fit right in if you

• 3+ years training large-scale deep learning models in multimodal domains (vision-language, audio, speech, or acoustic)
• Strong PyTorch skills with hands-on distributed training experience (DeepSpeed, FSDP, or similar)
• Deep experience with multimodal architectures - you understand how vision/audio encoders, projectors, and LLMs fit together (LLaVA, Qwen-VL, InternVL, Audio Flamingo, Omni Qwen, Audio Qwen, Whisper, HuBERT, Conformer, or similar)
• Hands-on with RLHF/alignment for multimodal: GRPO, DPO, reward modeling - not just for text
• Experience with video and/or audio sequence modeling: temporal modeling, long-context processing, efficient attention, streaming inference
• Track record of shipping models to production: you've hit latency targets and optimized inference, not just reported benchmark scores
• Comfortable with large-scale multimodal dataset curation: image-text pairs, video-instruction data, audio preprocessing, augmentation, synthetic data generation
• Familiar with MoE architectures and their tradeoffs for multimodal workloads
• Strong engineering fundamentals: clean code, version control, testing, documentation

A big plus

• Understanding of audio signal processing fundamentals (spectrograms, mel features, noise reduction)

Why White Circle

• Competitive compensation package, including equity
• Flexible time off
• Paid time off in line with your local regulations, no matter where you work from
• Work from Paris or London (hybrid) + relocation package for Paris
• Best medical insurance in France
• Learning and development support for courses, conferences, and opportunities to grow your skills
• 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

Process

1. 1. Introductory call with HR (25 min)
2. 2. Take-home test assignment
3. 3. Technical interview with Head of Applied Research (60 min)
4. 4. Final conversation with our CEO (45 min)