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Retell AI

Research Scientist - LLM

Conducts ML research to advance LLMs and audio models for real-time voice AI agents, focusing on reasoning, latency, and conversational quality. Prototypes models, designs evaluations, and bridges research to production systems requiring strong PyTorch expertise and experimental mindset.

225k – 400kRedwood City, CAAI ResearchOnsite
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About the role

Key Responsibilities

  • Research & Experimentation – Explore and develop new techniques across LLMs and audio models to improve reasoning, latency, and conversational quality in real-time systems.
  • Model Prototyping – Rapidly build and iterate on experimental models and pipelines, turning research ideas into working prototypes.
  • Evaluation & Benchmarking – Design novel evaluation frameworks, datasets, and metrics to measure performance on complex, real-world voice tasks.
  • Bridge Research to Production – Collaborate closely with engineering to translate research insights into deployable systems.
  • Human Feedback Loops – Develop methods to incorporate human evaluation into model improvement, especially for subjective conversational quality.
  • Advance the Frontier – Stay at the cutting edge of ML research and bring new ideas into Retell’s product and infrastructure.

You Might Thrive If You

  • Strong ML Research Background – Worked on advanced ML problems (e.g., LLM pre-training and post-training, transcription model training, text-to-speech model training, or multimodal systems).
  • Deep Technical Foundation – Comfortable with PyTorch, model architectures, and the math behind modern machine learning.
  • Experimental Mindset – Enjoy exploring open-ended problems and iterating quickly on ideas.
  • Bridging Theory & Practice – Translate research into systems that work in real-world environments.
  • Startup-Ready – Thrive in fast-paced environments with high ownership and ambiguity.
  • Collaborative & Clear Communicator – Explain complex ideas and work cross-functionally to drive impact.

Compensation & Benefits

  • Cash: $225,000 - $400,000 base salary
  • Equity: Offers Equity
  • Location: Redwood City, CA, US (100% Relocation Provided)
  • 100% coverage for medical, dental, and vision insurance
  • $70/day DoorDash credit for unlimited meals and snacks
  • $200/month wellness reimbursement
  • $300/month commuter reimbursement
  • $75/month phone bill reimbursement
  • $50/month internet reimbursement

Skills

LLMsPyTorchAudio ModelsMachine LearningModel ArchitecturesLlm Pre-TrainingLlm Post-TrainingTranscription ModelsText-To-SpeechMultimodal Systems

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