Principal Applied Research Engineer

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About This Role

Synthesia seeks a Principal Applied Research Engineer to join its video generation team as a senior individual contributor. Operating in person, this role drives the full technical stack for offline video generation, bridging pre-training and post-training to accelerate the delivery of advanced human-centric avatar models to market. Synthesia operates an AI video platform utilized by a significant portion of Fortune 100 companies, maintaining its headquarters in London alongside additional offices…

Job Description

Responsibilities

• Own the end-to-end technical direction for offline video generation across both pre-training and post-training phases
• Collaborate with research leadership and team leads to establish and execute a unified long-term roadmap
• Identify and resolve critical technical bottlenecks related to architecture, training stability, alignment, and coordination
• Speed up the transition from research to product by improving problem-solving, handoffs, and product management visibility
• Coach and mentor junior researchers and engineers to foster senior-level technical execution
• Contribute to team structuring and process refinement to support cohesive, high-velocity research execution

Requirements

• Demonstrated track record of training large-scale video generation models from scratch across multiple nodes using millions of hours of data
• Extensive experience with large-scale post-training techniques including RLHF, GRPO, and DPO
• Ability to evaluate and question data quality rigorously
• Capacity to balance multi-year strategic research planning with hands-on execution
• Strong cross-functional influence and communication skills without requiring positional authority
• Direct accountability for owning a major model generation or capability jump end-to-end from training to deployment

Qualifications

• Experience working across both pre-training and post-training stages on the same model family
• Background operating at scale with large distributed training runs, substantial compute budgets, and multi-million hour data pipelines
• Experience applying alignment and fine-tuning techniques in video or multimodal environments
• Familiarity with human feedback pipelines used in generative video or audio
• Prior experience leading or significantly influencing the technical direction of a research team while keeping a hands-on approach

Core Skills

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