Senior Research Scientist

Job Description

Want to work on one of the hardest unsolved problems in voice AI - making it actually sound like a human conversation?

Most voice AI falls apart the moment a conversation gets messy. Someone interrupts, emotions shift, the flow breaks - and the model can't keep up.

A small, ambitious SF startup is tackling exactly these problems, building speech models that handle natural conversation the way humans actually experience it. They have a working prototype and early commercial traction across several high-profile industry verticals.

The role

As a Senior Research Scientist, your focus is post-training - curating data, fine-tuning pre-trained speech models, and building the evaluation infrastructure that validates it all. You'll work on large-scale models with access to significant data resources.

What you'll do

• Shape the data that goes into post-training - sourcing, cleaning and structuring it for large speech models
• Supervised fine-tuning of pre-trained speech models
• Build evaluation workflows - automated and human-in-the-loop
• Drive measurable improvements in hallucination rates, instruction-following and generalisation

What you'll bring

• PhD in ML or related field with a strong publications record
• Hands-on experience training large speech models - ASR, TTS, or speech-to-speech
• Solid post-training and SFT experience

The founding team includes a founding engineer from a billion-dollar AI company where they co-created one of the first generative models in the field, alongside the co-creator of the first generative voice at one of the world's largest tech companies.

Compensation is between $400k-$500k base with generous equity.

Based in San Francisco, onsite. Relocation support for those in US and willing to make the move.