Multimodal ML Engineer

Whitecircle; Paris; Hybride; EUR 90 000 - 130 000; Plein temps

Avantages offerts par ce poste

Paid time off

Hybrid Paris work arrangement

Relocation package

Medical insurance for France team

Equity package

All needed hardware and software

AI tools subscriptions

Team off-sites

Résumé du poste

White Circle is seeking a Multimodal ML Engineer to train and ship vision, audio, video, and speech models for an AI safety platform. You will design experiments, build data pipelines, and optimize models for production at scale.

The role requires hands-on experience with PyTorch, distributed training, and multimodal architectures. Join a small, results-driven team focused on safety, reliability, and policy-based AI.

Qualifications

• 3+ years training large-scale deep learning models in multimodal domains.

Responsabilités

• Train and fine-tune large-scale multimodal models from scratch and 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 to training-ready datasets, including synthetic data generation.
• Train and optimize MoE architectures for efficient multimodal inference.
• Deploy models end-to-end from research checkpoint to production serving.

Connaissances

PyTorch

Multimodal models

Deep learning

Model deployment

RLHF alignment

Video/audio processing

Distributed training

MoE architectures

Data pipelines

Outils

DeepSpeed

FSDP

Description du poste

TLDR

Multimodal ML Engineer to train and ship vision, audio, video, and speech 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 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

Requirements

• 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

• Paid time off in line with your local regulations, no matter where you work from
• Work from Paris (hybrid) with a relocation package available, or work from London (note: we are unable to provide relocation support for London-based roles)
• Comprehensive medical insurance for our France-based team (please note that we are in the process of setting up our UK office and therefore cannot offer medical insurance for London-based roles yet)
• Meaningful equity package
• 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