Research Scientist - Interactive Avatars

Synthesia is the world’s leading AI video platform for business, used by over 90% of the Fortune 100. Founded in 2017, the company is headquartered in London, with offices and teams across Europe and the US.

As AI continues to shape the way we live and work, Synthesia develops products to enhance visual communication and enterprise skill development, helping people work better and stay at the center of successful organizations.

Following our recent Series E funding round, where we raised $200 million, our valuation stands at $4 billion. Our total funding exceeds $530 million from premier investors including Accel, NVentures (Nvidia's VC arm), Kleiner Perkins, GV, and Evantic Capital, alongside the founders and operators of Stripe, Datadog, Miro, and Webflow.

About the role

As a Research Scientist, you will join a team of 40+ researchers and engineers in our R&D department, working on the frontier of generative AI with a focus on avatar-centric, interactive video diffusion models.

This is a unique opportunity for experts in machine learning and diffusion models to shape the future of AI video agents that listen, respond, and react like humans. As part of our Interactive Avatars team, you'll build models that hold natural, real-time conversations: understanding what a user says and how they say it, then responding with appropriate turn-taking, backchannels, gaze, and facial and body reactions. You'll join a team that moves fast, iterates often, and turns breakthrough research into product capabilities that ship.

What you'll do

• Contribute to the research direction for dyadic interaction modeling, and own well-scoped research problems end to end.

• Advance the state of the art in the perceptual layer of interactive agents, including understanding user audio and video and generating contextually appropriate reactions.

• Post-train multimodal models to generate rich, natural dyadic interactions from user audio and video inputs.

• Adapt diffusion models to new conditioning signals, such as conversational state, turn-taking, and listener cues.

• Build robust evaluation frameworks and test suites for continuous tracking of interaction quality.

• Partner with our data team to define data needs and shape high-quality datasets.

• Run rigorous experiments, and share findings that inform the team's technical decisions.

What we're looking for

• A strong ML background and hands-on experience with diffusion models, ideally for video or avatar generation.

• Publications at top-tier venues (e.g., CVPR, ICCV, ECCV, NeurIPS, ICML, ICLR, SIGGRAPH) in areas such as world models, dyadic interaction, or video diffusion, or equivalent demonstrated impact.

• Experience taking research ideas through to working implementations, and motivation to see them reach production.

• Proficiency in PyTorch and modern ML tooling for large-scale training.

• Clear communication of hypotheses, experiments, and results.

Nice to have

• Experience with real-time or streaming generation, including autoregressive video diffusion.

• Distillation or other techniques for low-latency inference.

• Audio-driven facial, gesture, or full-body motion modeling.

• Conversational modeling, such as turn-taking, backchanneling, or listener-response generation.

• Experience mentoring students or junior researchers.

Why join us?

• Build production-scale video foundation models in a fast-growing Generative AI company

• Work on human-centric video generation with real-world impact

• Tackle hard problems in scaling, stability, and controllability

• Influence the direction of next-generation synthetic human technology

• Join a highly technical, high-ownership environment where your work ships

If you want to work on cutting-edge generative video models and see your research power real-world products, we’d love to talk.Our culture

At Synthesia we’re passionate about building, not talking, planning or politicising. We strive to hire the smartest, kindest and most unrelenting people and let them do their best work without distractions. Our work principles serve as our charter for how we make decisions, give feedback and structure our work to empower everyone to go as fast as possible. You can find out more about these principles here.