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Senior Research Scientist (LLM post training)Join to apply for theSenior Research Scientist (LLM post training)role atPolyAI Senior Research Scientist (LLM post training)21 hours ago Be among the first 25 applicants Join to apply for theSenior Research Scientist (LLM post training)role atPolyAI Get AI-powered advice on this job and more exclusive features. PolyAI automates customer service through lifelike voice assistants that let customers lead a conversation. Our voice assistants make it possible for businesses to deliver outstanding customer service that rivals their human agents. Our customers, which include the world’s leading logos, are expanding how they use our platform, driving automation of critical customer service operations and integrating PolyAI into their daily customer service workflows. We are looking for aSenior Research Scientistto join our world-class team and lead cutting-edge work on large language model (LLM) post-training. This is not just about applying standard fine-tuning techniques - it's about building the future of dialogue systems with novel approaches to reasoning, reinforcement learning, audio-first LLMs, and more. As aSenior Research Scientistat PolyAI, you’ll lead impactful research projects from ideation through to deployment. You’ll be driving innovation in how we train and adapt LLMs for real-world conversations - spanning voice, text, and multimodal contexts. You'll work on frontier techniques such as: Conversational reinforcement learning Streaming and continuous turn-taking Audio-native LLMs Distillation of reasoning models Long-context You’ll also play a key role in shaping the scientific direction of our research, mentoring junior colleagues, and collaborating cross-functionally to bring research into production. Responsibilities: Lead and execute complex research projects with clear business impact. Design and implement novel post-training strategies including preference tuning, reward modeling, and synthetic supervision. Develop innovative model architectures and training approaches for conversational AI, including speech-aware and multimodal models. Conduct empirical studies to assess model performance in live deployments and iterate quickly based on real-world data. Generate, collect, and annotate training data - including synthetic and real-world conversational datasets - with an eye for quality and bias mitigation. Design robust evaluation metrics and benchmarks for LLM-based assistants in customer service domains. Work closely with engineering and product teams to integrate research into production environments. Collaborate with legal and compliance teams to ensure responsible use of data and models. Stay current with academic and industry advances in LLMs, ASR, TTS, RLHF, and multimodal learning. Requirements: PhD in Machine Learning, Natural Language Processing, Computer Science, or a related field. 5+ years of hands-on experience in deep learning. Proven track record of research innovation, including published work or deployed systems. Strong programming skills in Python and deep learning frameworks like PyTorch. Demonstrated expertise in at least one domain area such as reinforcement learning, conversational AI, audio modelling, or LLM alignment. Experience leading projects end-to-end, from ideation to deployment. Excellent communication skills with the ability to write clear technical documents and explain complex concepts to diverse audiences. Comfortable working in ambiguity and driving clarity through experimentation and data. Preferred Qualifications: Experience with speech technologies such as ASR and TTS. Familiarity with cloud environments (AWS, GCP, Azure). Exposure to RLHF, reward modelling, or human preference data collection. Prior work on real-time systems, streaming inference, or memory-efficient model deployment. PolyAI Benefits - UK Participation in the company’s employee share options plan Flexible working from home policy plus a one-off WFH allowance when you join Work from outside of the UK for up to 6 months each year Yearly learning budget Private healthcare and dental cover, discounts on gym members and relaxation apps, and access to a range of mental health programs Interview Process 1. Quick intro call with Talent (15 - 30 mins max) 2. Interview with Hiring Manager, 45 mins 3. Loop stage: 1x coding and 1x ML, both 45 mins 4. Final with CTO Seniority levelSeniority level Mid-Senior level Employment typeEmployment type Full-time Job functionJob function Information Technology and Engineering Industries Software Development Referrals increase your chances of interviewing at PolyAI by 2x Sign in to set job alerts for “Research Engineer” roles.London, England, United Kingdom 6 days ago Oxford, England, United Kingdom 6 days ago London, England, United Kingdom 6 months ago Edinburgh, Scotland, United Kingdom 1 week ago Southampton, England, United Kingdom 1 day ago London, England, United Kingdom 2 days ago Southampton, England, United Kingdom 5 days ago London, England, United Kingdom 1 day ago Birmingham, England, United Kingdom 1 day ago Stoke-On-Trent, England, United Kingdom 1 day ago United Kingdom $100,000.00-$150,000.00 4 weeks ago London, England, United Kingdom 6 months ago Birmingham, England, United Kingdom 5 days ago Sports Modelling Data Scientist (relocation to Costa Rica)Manchester Area, United Kingdom 1 week ago Rotherham, England, United Kingdom 1 day ago Bradford, England, United Kingdom 1 day ago London, England, United Kingdom 3 weeks ago Bradford, England, United Kingdom 5 days ago London, England, United Kingdom 6 days ago Birmingham, England, United Kingdom 1 day ago We’re unlocking community knowledge in a new way. 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