Senior Research Scientist

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.

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.

• 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

• 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 and $500k base with generous equity.

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