Retell AI · 5 hours ago
Senior Machine Learning Engineer
San Francisco Bay Area
Full-time
Onsite
Senior Level
$215K/yr - $290K/yrRetell AI is using cutting-edge voice AI to reimagine call centers. The Senior Machine Learning Engineer will build production models for voice agents, fine-tuning large language models and deploying them in high-traffic systems.
Artificial Intelligence (AI)AudioCall CenterGenerative AITelecommunications
Responsibilities
Train & Tune Models – Fine-tune LLMs and audio models to maximize speed, accuracy, and production-readiness—pushing the frontier of real-time AI voice experiences
Benchmark & Evaluate – Build datasets, define rigorous metrics, and measure model performance across high-impact voice AI tasks to guide development
Deploy to Production – Work closely with engineering to ship models, monitor them in the wild, and ensure they stay fast, reliable, and accurate at scale
Run Human Evaluations – Build scalable pipelines to collect structured human feedback, benchmark subjective quality, and inform model iterations
Level Up Infrastructure – Design and maintain the ML infrastructure needed for fast experimentation, robust training, and continuous deployment
Qualification
Required
ML Engineer with Real-World Experience – You've trained and shipped models in production
Fluent in Modern ML Stack – You know your way around Python, PyTorch, and today's ML tools—from training pipelines to evaluation benchmarks
Execution-Oriented – You move fast, take ownership, and focus on solving real problems over perfect ones
Startup-Ready – You're adaptable, resilient, and energized by ambiguity and fast-changing priorities
Clear Communicator & Team Player – You collaborate well across functions and push decisions forward
Preferred
Bonus if you've worked with LLMs or audio models
Benefits
100% coverage for medical, dental, and vision insurance
$70/day DoorDash credit for unlimited breakfast, lunch, dinner, and snacks
$200/month wellness reimbursement (gym, fitness classes, etc.)
$300/month commuter reimbursement (gas, Caltrain, etc.)
$75/month phone bill reimbursement
$50/month internet reimbursement
Company
Retell AI
Retell AI is the AI voice platform that helps corporate call centers automate calls indistinguishable from human.
Founded in 2023
11-50 employees
H1B Sponsorship
Retell AI has a track record of offering H1B sponsorships. Please note that this does not
guarantee sponsorship for this specific role. Below presents additional info for your
reference. (Data Powered by US Department of Labor)
Distribution of Different Job Fields Receiving Sponsorship
Represents job field similar to this job
Trends of Total Sponsorships
2025 (5)
2024 (3)
Funding
Current Stage
Early StageTotal Funding
$4.68MKey Investors
Alt CapitalY Combinator
2024-04-03Seed· $4.55M
2023-11-01Pre Seed· $0.12M
Leadership Team
Evie Wang
Co-Founder
Recent News
Company data provided by crunchbase